It's a hard list. There are some great products coming out that I'm looking forward to.
Windhaven
Swashbuckling Adventure (7th Seas)
Occult Lore
Cults of Law & Chaos: I've been highly unimpressed with Chaosiums support for D20 but I'm always willing to look.
Path of the Sword: Dying to see more examples of the Legendary PrCs
Game Mastering Secrets 2nd ed. I'm a sucker for these books. I rarely see anything that strikes me as "Wow, I never thought of that," but often see stuff that makes me go, "Hmmm, I haven't used that in a while or tried that in the game."
Villain Design Handbook: If this is half as good as their (Kenzer) Kalamar Player's Guide, I'm so there.
The Slayer's Guide to Dragons: I'm not terribly impressed by Gary's D20 material yet and haven't really liked the Slayer's guides, but hope sprints eternal.
Quintessential Elf: I like the series thus far (where's the Wizard eh?). More important though, it'll be interesting to see how this compares with other racial books coming out.
Urban Blight: Since I started running my campaign, I've noted a lack of city based goods.
Arcane Mysteries: Blight Magic: Sucker for magic books.
Codex Germania: I'll state up front I haven't liked the Maze series but I love the Vikings so it'll be interesting to see if the mechanics and other material in this book is sound. Thank god Robert doesn't have his own game system of this would be dual slatted for that too.
Waysides & Fields of Blood from Eden. Heck, throw Secrets of the Ancients, the vignitte book that you don't even hear about anymore in there too.
AEG's Mercenaries: Hated war but I've enjoyed the other one word books in the series.
Everquest: It'll be interesting to see how compatible this is. If it's not more compatible than Wheel of Time, I suspect that it'll flop.
Hammer and Helm: I'm interested to see how this and the giant book from Pardigm match up. In the new Polyhedron they talked about working together a little and it does indeed look like the covers match and make one larger cover. Interesting.
Epic Level Handbook: Well, since the start of 3rd ed, they've boasted that it's meant to handle various levels of play. Bring it on I say.
There are numerous other books but for now, I think that list will do.