The disks:
Anything by Ray Charles -- like Mel Lyman said, Ray contains all music.
John Coltrane -- A Love Supreme
Muddy "Mississippi" Waters Live (with Johnny Winter and Jerry Portnoy)
Bill Monroe, best of
Rahsaan Roland Kirk -- Dog Years In The Fourth Ring (It's a 3-disk box set -- is that cheating?
Miles Davis -- Kind Of Blue
Charles Mingus In Europe (live set with Eric Dolphy and Jaki Byard)
First demo disk from my current band

Book: A field guide to desert island flora and fauna (publisher unknown). At least, it might give me a handle on what is safe to eat around there. Extra points for the field guide that says everything -- including the plants -- taste like chicken.

Luxury item: OK, I'll fudge here. Harmonica is not a luxury item. Got it? It's a necessity. In fact, I'll probably be playing it while the ship is breaking to pieces (they did that on the Titanic, right?) I am prepared to take this case to the Desert Island Provisioning Authority. If I lose my case, then my belt loaded with harmonicas will be the luxury item. Should I win, then the luxury item will be an ax.