Enforcer
Explorer
Excluded: Eberron (and homebrew, as it would've been the runner up if allowed)
Runner Up: Forgotten Realms
What do my top picks have in common? Kitchen sink. They can include all the splats, rules, and whatever that I want (or specifically don't want) without having to pound square pegs into round holes. There's a place for all the weird stuff I like, like psionics or my very recent interest, the Tome of Battle: Book of 9 Swords.
Runner Up: Forgotten Realms
What do my top picks have in common? Kitchen sink. They can include all the splats, rules, and whatever that I want (or specifically don't want) without having to pound square pegs into round holes. There's a place for all the weird stuff I like, like psionics or my very recent interest, the Tome of Battle: Book of 9 Swords.