We might want to tuck this away as TO. Can you imagine some poor DM who looks at this thread and sees CR 200+ creatures?
Examples of abandoned 3.0 rules: old psionic combat, polymorph other/self
These were abandoned to simply things, when they were replaced with psionic powers and polymorph
Examples of unabandoned 3.0 rules/books: Arms and Equipment, Book of Vile Darkness, Lords of Darkness, Masters of the Wild, Savage Species, Song and Silence, Sword and Fist
There are many things used in those books, despite being exclusively 3.0, so how can you say that just because something never was reprinted, it is obsolete or abandoned.
The psionic combat is out. Its been 'updated' and therefore the old version is invalid. Polymoprh other/self are specifically mentioned in the update booklet to both now be "polymorph," hence the phylactery use.
The 3.0 books are still usable, though. Its just you have to update some of the material to use it in 3.5