As commented on in other threads, it's somewhat debateable whether these are really are the sixty greatest OTR shows of the 20th Century. I thought I would offer my thoughts on the matter. I should probably note right off that I didn't listen to all of the contents and will state which ones I didn't.

1. War of the Worlds (MTotA). How could you have a collection like this and not have this episode? It's kind of fun imagining the folks of the time who were listening to Chase and Sanborn check to see what else was on and come across this. Even if this sort of thing hadn't been made illegal, you just couldn't do this sort of thing on TV (not without a massive budget, anyway).
2. Who's on First? (Abbott and Costello). Really another obvious choice. This was the first time I had heard the Feller gag and I thought it was pretty good.
3. Red Wind (Phillip Marlowe). Skipped this one, as I'm not a big fan of Marlowe or noire detectives in general.
4. Chase and Sanborn. Also skipped this one. I suppose it seemed like a good idea at the time to also include the episode that aired opposite The War of the Worlds, though someone here differs on that IIRC.
5. Britt Ponset's Christmas Carol (The Six Shooter). As commented elsewhere, a rather bland Christmas episode. Choosing The New Sheriff or Crisis at Eastercreek might have been a better idea as not only were these episodes good, they also show how strange The Six Shooter could be.
6. Report Card Blues (The Baby Snooks Show). Mildly amusing in spots, but I'll bet this episode gives apopletic fits to people who oppose corporal punishment.
7. Lienengen vs. the Ants (Escape). This is one that is always cited as one of the great episodes of Escape and it is a fine story.
8. I Can Get It for You Wholesale (Fibber McGee and Molly). I don't think I've ever encountered an episode of Fibber McGee and Molly that I didn't enjoy. I imagine this one was chosen due to it having been broadcast two days after the attack on Pearl Harbor.
9. On a Note of Triumph. Skipped this one.
10-11. Brave New World (CBS Radio Workshop). Skipped this one too, as Brave New World just isn't my brand of science fiction.
12. Burns and Allen. Another skip. I'm not a big fan of George and Gracie.
13. Jack Benny Program. Moderately amusing, though I don't think this was one of his better running gags.
14. The Jazz Singer (Lux Radio Theater). Skipped.
15. Sorry, Wrong Number (Suspense). As I've stated elsewhere, I consider this episode highly overrated. Certainly not worth broadcasting it eight times as well as two movies (one adapted to Lux Radio Theater) and a novel.
16. Miracle for Christmas (Grand Central Station). Skipped, as I can't abide syrupy Christmas episodes.
17. The Road to Hollywood (Philco Radio Time). Skipped.
18. The Corpse Said Ouch (The Saint). There were a couple of bits that had me rolling my eyes, Vincent Price is just so good.
19. From Here to Boston (Have Gun, Will Travel). A lot of serieses don't get particularly good final episodes, but this one managed to tie up things neatly.
20. Muted Silver Moonbeam Chimes (Vic and Sade) Skipped, as I've never really understood the appeal of this show.
21. Christmas Show (Lum and Abner). Same as above, though my dad is a big fan of this show.
22. We Hold These Truths. Skipped.
23. Arthur Godfrey Time. Skipped.
24. Walter Winchell Show. Skipped.
25. Nightfall (X Minus One). I don't care for the science fiction of Issaac Asimov, but decided to give it a go. About halfway through, I hit the fast forward button in disgust.
26. Origin Retold (Superman). A relatively self-contained episode from a serial, once again making you despair of the reasoning abilities of the citizens of Metropolis.
27. The Hitchhiker (Mercury Summer Theater). This was the first encounter I had with OTR (the script was in a middle school reader). Therefore, I have a soft spot for this one.
28. Death Rides the Highway (Big Town). Skipped this one, though if it's the one I think it is, I can understand the comment someone made about how preachy it is.
29-33. The Todd Matter (Yours Truly, Johnny Dollar). It's one of the five parters from Bailey's first season. What more need be said?
34. The Undecided Molecule (Columbia Presents Corwin). Skipped.
35. The Martian Chronicles (Dimension X). Skipped, as I'm not too keen about Ray Bradbury either.
36. The Eddie Cantor Show. Skipped.
37. Three Skeleton Key (Escape). Another frequently cited episode, and it is quite good (and it has Vincent Price).
38. The Adam and Eve Sketch (Chase and Sanborn). Skipped.
39-40. Native Land (The Cavalcade of America). Skipped.
41. Fred Allen Show. Skipped.
42. Cat Wife (Lights Out). I could hardly imagine a worse choice. If they had to have a Lights Out with Boris Karloff, why couldn't it have been Death Robbery, which is halfway decent.
43-44. The Money or Your Life Episode and the Aftermath (Jack Benny Program). Plenty of good stuff. I particularly like how Jack kept touching up the story of what happened to make himself look better.
45. Dick Tracy in B-Flat (Command Performance). Skipped.
46. Fourteen August (Columbia Presents Corwin). Skipped.
47. .22 Rifle for Christmas (Dragnet). I had two different reactions to this one. The first was a very sick feeling in my gut over what happened. The second was being pleased that finally I had heard a Christmas episode that wasn't dripping with syrupy sentimentality.
48. White God (The Shadow). The racial stereotyping in this one really bugs me (though it isn't as bad as The Isle of Fear). That, plus the plot being implausible even by Shadow standards, makes this one an overrated classic.
49. The Death Bed Caper (Sam Spade). Skipped.
50. The Bickersons. Skipped
51. The Shadow of Death (Inner Sanctum). This one was a gas, especially the scene where the protagonist demonstrates to the doctor the dream he had where he kills him.
52. McGee's Christmas Gifts (The Great Gildersleeve). An average episode with some cute bits. Probably chosen because this one had a definate link to Fibber McGee and Molly.
53. I Love Lucy. This was a rather inane choice.
54. Johnny Got His Gun (Arch Oboler Plays). I gave up on this one partway through as it was rather hard to follow (not to mention deadly dull).
55. Backseat Driver (Suspense). Jim and Marian Jordan on Suspense in a well written story makes for a really strange episode.
56. Origin Show (The Lone Ranger). I know a lot of folks here don't care for this show, but for me, it's a bit of a guilty pleasure. Overall interesting, though the bit with the buffalo was kind of weird.
57. The Photographer (Gunsmoke). A rather average episode, though I admit I really can't think of an episode of Gunsmoke that's spetacular.
58. Mell-A-Lot (Let's Pretend). I really was going to try to listen to this one, but the Cream of Wheat commercial at the beginning kind of scared me off.
59. Deadly Merchandise (Bold Venture). What is it with Bogart and radio? Just about everthing I've heard with him on it is kind of mediocre and this is no exception.
60. The Thing on the Fourble Board (Quiet, Please). Easily one of the most disturbing episodes I've ever heard.

Comments?

I've been trying to listen through them all. Here's what I've done so far:

1. War of the Worlds--Well done, a little overfamiliar and the gimmick is just that after the first listening, but still compelling, especially when Frank Readick's reporter character does his fateful description.

2. Abbott and Costello--Abbott and Costello DID do other material besides "Who's on First," but a good pick anyway. The Bob Feller joke is VERY one-note, and to me isn't as funny. Oh well.

3. Philip Marlowe--This is a very good show, Van Heflin captures the flavor of a depressed and down-and-out Marlowe better than Gerald Mohr.

4. Chase and Sanborn--Actually, this is pretty good for an episode picked for novelty. Nelson Eddy, who was like the Gomer Pyle of the '30s (weird speaking voice, classical singing voice) even gets to sing and chat. The Halloween story by Bergen is typical Bergen/McCarthy--hilarious.

5. The Six Shooter--It is indeed rather bland. There is absolutely no reason to do A Christmas Carol, and having it told as a conversational story saps any drama left.

6. The Baby Snooks Show--Baby Snooks is good for a few laughs, and it's fun to enjoy even though it's a rather hoary premise.

7. Escape--Great episode that can make you squirm at times.

8. Fibber McGee and Molly--I like this show because it's a laidback comedy but not too laidback (a la Vic and Sade). The Japan joke packs a punch.

9. On a Note of Triumph--Stick with it through the overdramatic histrionics. This actually becomes a VERY ahead-of-its-time feature--can you imagine any other program sitting down and saying "Have we actually accomplished anything?" in 1945.

10/11. CBS Radio Workshop--Brave New World works well, and it is neat to have Aldous Huxley narrate.

12. Burns and Allen--Surprisingly off considering Jack Benny is the guest. Could have been better.

13. The Jack Benny Program--Things get cluttered at the end with simply too many guests to work with (it doesn't help to have so many conflicting stylists) that funny people like Groucho, Sinatra, Burns, and Kaye get muted.

14. Lux Radio Theater--Jolson does well, even though I haven no idea why this was selected.

15. Suspense--Indeed overrated but worth listening to at least once to catch Moorehead's tour de force.

16. Grand Central Station--I think there should be a ban on any Christmas episode that has Jesus as the guest star, but this is better than the premise seems to indicate.

17. Philco Radio Time--It's Bing, Bob, and Dorothy. Can't get much better.

18. The Saint--Not much of a mystery, but can you really turn down Vincent Price in anything?

19. Have Gun, Will Travel--A good final episode, as it is so laidback. The ending is touching.

20. Vic and Sade--I don't like this show; people are right--it IS like listening to a real-life married couple, but then I ask "so what?"

21. Lum and Abner--Do you like Christmas episodes with a huge dose of moralizing? Then you'll love this. Not really bad though.

22. We Hold These Truths--Doesn't seem very interesting now, and compared to On a Note of Triumph, it's just propaganda.

23. Arthur Godfrey Time--"Let's listen to Arthur Godfrey and the wonders of dead air. Isn't that...good, Tony Martin?" "Yes, sir."

24. Walter Winchell--I would like to have Winchell and Godfrey sit down and kill each other to destroy the excesses of their programs--one is hyper slow, the other hyper fast.

25. X Minus One--Uh, there is no ending, but other than that this is fine. Unfortunately, it is all about building up to the ending.

26. Superman--Don't we all know the origin?

27. Mercury Summer Theater--Good, good, haunting piece. Orson Welles is great.

28. Big Town--Wow, bad driving is bad! Never would have figured that out! Thanks, Edward G. Robinson and Ona Munson! I'm guess I'm being harsh, but this is definitely not the best episode.

(This is where I am, even though I have listened to some of the later shows)

36. The Eddie Cantor Show--Fun and funny, but with this cast (even the bit players--Dinah Shore, Harry Von Zell, and the Mad Russian), could you really go wrong?

41. Fred Allen--Absolutely friggin' hilarious, but Jack and Fred always rock. The ending with hapless announcer Kenny Delmar trying to read the commercial while Jack Benny shouts "Give me back my pants!" is a masterpiece (you had to be there).

43-44. Jack Benny--The first episode really is just OK until the punchline, but the second packs a lot of funny stuff into it (including the Ink Spots!), and Bing Crosby was always a great guest star.

54. Arch Oboler's Plays--Well, it's not much of a story and not much of anything, but the ending with Jimmy Cagney railing against the Big Guys really works. Really sad when you consider that WWII was a few months off.

57. Gunsmoke--Uh, well, it's sort of predictable (check--make it VERY predictable), even though the basic idea and set-up works okay. "Shakespeare" with Hans Conried is better.

There are also some shows that should have had an episode picked but didn't. I'm sure that they could have dumped Arthur Godfrey or Walter Winchell or I Love Lucy and no one would have noticed. Among the shows that should have been included are The Black Museum, Box 13, Frontier Gentleman, The Whistler, Tales of the Texas Rangers, and The Green Hornet.

Uh, what about Amos and Andy? I hear they were pretty big on the radio too...

The Mysterious Traveler would have also been a good choice.

So when we all switch to watching super videodiscs or something, will there be a Television Spirits that releases the best of television?

Will future people ponder the inclusion of a newscast by Walter Cronkite or an episode of Entertainment Tonight?