The Campaign Builder's Guild

K, thanks peoples...  I'm putting in my order now, i'll let you know how the books turned out with nice and shiny reviews when they get here.

~~And now for something completely different~~

I bought Spell Compendium a couple days ago...I urge anyone and everyone who uses spells in their campaigns to buy this thing!

It's a little late, but I'll give my opinions.

I don't own any Complete books, any Races Of books, the MM3, PHB2, DMG2, or any Eberron books. My most recent purchases were Libris Mortis and the BoVD, which I can say were VERY well-made. Libris Mortis is an especially worthy prize, and though I have seen many complaints it is a very useful book to me.

Tome of Magic looks like a very good buy, though I don't have it myself. As do Lords of Madness and Heroes of Horror.

You've said you buy 3.5 only, but I wouldn't suggest restricting yourself. There are a lot of good buys in 3.0 that you may find useful for inspiration if not for the crunch (since there are updates for many books). Savage Species is a waste in my opinion, and the ELH is as well beyond level 30. Manual of the Planes is a nice book for flavor and I hear it's better than the Planar Handbook. The MM2, Fiend Folio, and the BoVD are nice. BoED not so much, though the good-aligned undead template in there was cool.

For the record, I'll give you a list of what I own, so you can see what I have used to create my setting:

3.0
PHB, DMG, MM, MM2, Masters of the Wild, Defenders of the Faith, Tome & Blood, Savage Species, Manual of the Planes, Epic Level Handbook, Book of Vile Darkness, Book of Exalted Deeds, Arms and Equipment,
3.5
Libris Mortis, Fiend Folio, Unearthed Arcana, Expanded Psionics Handbook (barely viewed, for the record I have yet to use psionics in any of my worlds for a very long time)
Forgotten Realms
FRCS, Monsters of Faerun, The Silver Marches, Unapproachable East, Magic of Faerun, Races of Faerun, Player's Guide to Faerun

The only ones I've used extensively have been MotP, BoVD, Libris Mortis, and Unearthed Arcana.

Make sure that you look at a book a little before you buy it. When I got Libris Mortis I didn't even know it existed prior to that visit to the bookstore. I walked in and saw it, read a couple pages and saw some wicked monsters, and bought it within ten minutes. Rappan Athuk (that Sword&Sorcery adventure) seemed totally uninteresting from the read, though.