Oriental Adventures
Manual of the Planes
Maybe:
Monster Manual II (there are some broken critters in it, but the rest are okay and some are pretty neat; includes stuff like gem dragons, elemental wierds, jermlaines, grells, brass golems, fihyrs, clockwork horrors, ankylosaurs, hook horrors, linnorms, myconids, neogi, nimblewrights, phoenixes, lawful/chaotic planetouched, spirits of the land, wystes, and the warbeast template)
Also, possibly:
Psionics Handbook (mainly just if you think 3.5 XPH is broken, then 3.0 PsiHB may be more your cup of tea; hardly anything in the way of broken powers, so hardly anything to just houserule away; no augmentations; no psionic focus, just more ways to spend power points and thereby not overshadow spellcasters; no wierd races; no overchanneling or wilders or crazy extra-actions madness; just make a houseruled limit on Psychofeedback and Fission, and remove Schism if you don't use 3.0 Haste)