Ah, Ok. Apologies if I sounded a bit brusque - darned tonal inflections not carrying well over the internet...
Any I'd recommend? All of them!
But that's just me; I'm a score enthusiast, and I consider the soundtracks to be essential to one's enjoyment of the series, just below having and watching the actual movies and TV shows on DVD or whatever.
Here are a few quick notes and observations:
Vol. 1 - An extended album version of The Main Title (just over two minutes, and focusing on the "adventure" backbone of the theme, omitting the jazz and such), plus music from Verdun 1916, Peking 1910, Paris 1916 and Barcelona 1917. All good stuff IMO, but my favorites are the rather heavy dramatic stuff from Verdun and the comically fiery Barcelona, with its Rimsky-Korsakoff's Scheherazade and flamenco flourishes.
Vol. 2 - The Main Title again, this time in a short version more like what's in the opening titles to the show, plus music from Vienna '08, German East Africa / The Congo '16 & '17, London '16, and British East Africa '09. Here I most enjoy the serious treatment of the Oganga episodes, with poignancy added from a bit of Bach, reflecting the Bach-loving Albert Schweitzer, and the delicate romantic parts from the London episode.
Vol. 3 - Scandal of 1920, Mystery of the Blues and Princeton '16. Arguably the most thematically-unified of the four volumes, this one features a lot of source cues in the first two episodes. A lot of soundtrack fans bristle at this sort of thing, but I love it; some of the jazz / blues stuff from Mystery of the Blues is probably my most-played music from these CDs, whereas my favorite tracks on the other albums are score cues (then again, the other albums have far less source music on them).
Vol. 4 - Ireland '16, Phantom Train of Doom and Northern Italy '18. My favorite parts of this are from Phantom Train, with all the Williams-ish material; it really helps tie the TV series to the features.
I consider all four essential to my Indy library, right alongside the movie soundtracks. I do wish there were additional volumes with more music, but there you go. Each of these is a single CD, but they're quite long - the shortest is Volume 3, and it's still over 70 minutes; the other three are all over 75, and the four of them combined run close to five hours.
Considering the series' too-short run, I think this makes this show one of the TV shows with the most score represented on CD, though there's still a lot missing. Everything on the four discs comes from episodes scored by the series' two main composers, Laurence Rosenthal (who composed the theme) and Joel McNeely, who between them did a lot of the show, but there are also a bunch of episodes scored by others. I really wish there had been even more - but then, even the soundtracks for the three movies aren't exactly comprehensive, either, though I'm hoping that'll change with the reported forthcoming Concord reissues.
Anyway, aside from the music itself all four feature pretty nice presentations, with insert booklets with a lot of nice photos, plus notes on their scores by the two composers. The fourth volume also has some brief additional notes by George Lucas; I see someone else went and posted them somewhere around here in another thread.
Apologies for the digression...