Both of the games I run are 3.5. I've yet to decide if anything from Unearthed Arcana will make its way into my game, so we run pretty much stock. We do use a variant action dice system ala Spycraft, which I may ditch in favor of the action points mechaninc in Unearthed Arcana.
I play in a homebrew game that is a modified 3.5 d20, though after playing All Flesh Must Be Eaten, we may take that campaign out of d20 alltogether, unless d20 Conan has enough of a feel to it to make us stay in the realm of the icosahedron.