Every once in a while, I like to make lists. I may have made this list before, in which case it probably hasn't changed too much. This is the list of 3e (or 3.5) books that I want to buy but still never got around to. Actually, that's not exactly true. This is the highish priority list. There's a few more also that I wouldn't mind picking up, although I wouldn't go too far out of my way for them. Anyway...
The rest of the Complete series that I don't already have:
As you can see, I don't much care for spellcasters. I mean, heck; I've already got Complete Psionic for cryin' out loud, before I got any spellcaster completes. But; I want to complete the set.
The rest of the monster manuals:
Monster Manual IV
Yeah, that's it. I count Fiend Folio as a MM. But I've already got it.
The rest of the environmental books:
I actually am not counting Dungeonscape. I don't care about that one. I've actually only got Frostburn, but holy crap, great idea for a line of sourcebooks.
Other books I want that aren't exactly part of a series per se:
Player's Handbook 2
Heroes of Horror
That's nine books. In nine books, I could be done.
Of course, I could also be not done. If I get past those nine books, I've got another list of lower priority books to buy.
The rest of the Races series:
Races of Stone
Races of the Wild
Races of the Dragon
I bought Races of Destiny on the cheap years ago, and I wasn't impressed with it enough to make a point of collecting the rest. But, probably, one of these days I'll get around to it.
Two of the Complete books I've never been that interested in, but the completist in me will probably eventually drive me to buy:
A few other books, that belong to no series per se that I can percieve:
Magic of Incarnum
Tome of Magic
Tome of Battle: The Book of Nine Swords
So; ten more. Low priority, but still; I'd eventually like to have them.
Of course, then we start on the Forgotten Realms and Eberron books that I don't have.
D'oh. I've got a lot of buying to do after all.
Still; only the first nine are really "high" priority, and by "high" I mean, even though they've been out of print for a year and a half (or longer) I still haven't gotten around to buying them. High being a very relative term in this instance.