Have you thought of hopping out of the D&D game and trying something else for a few sessions? Look into Savage Worlds, Call of Cthulhu, M&M, Buffy/Angel, Star Wars, Warhammer FRP, or even (especially?) something like Paranoia for a one-shot. Or, heck, even one of the many freely available retro-clones like S&W or OSRIC. Then, segue back into the
3e D&D campaign that is, by all appearances, your gaming passion.
Sometimes a change of pace is all you need to keep your games feeling new and exciting.

I've found it helps my DMing a lot, and my players like doing something different once in a while.
-O