Well, I'll be replacing the Core rulebooks, of course. Probably not right away, and not all at once, but eventually.
I'll be pouncing on the re-release of the Creature Catalog.
Also looking forward to The Quintessential Chaos Mage to replace my copy of Encyclopaedia Arcane: Chaos Magic. The latter is a great idea, but has some weaknesses. It'll be good to see the revised edition, especially since it should be 3.5 compatible.
Probably pick up the Ravenloft DMG, which will provide updates to that setting. Hopefully they revise the monster book for that setting as well (haven't picked it up, thankfully).
The only other thing I've got is some Dragonstar books, which really won't be affected that much. I'm probably going to convert all my DS stuff to use d20 Modern rules and D&D 3.5 classes, from the SRD. So, no real revision necessary.