We're a bunch of old grognards who usually play straight 3E, when we're not playing d20modern.
(We are playing a lot of d20modern - nice, clean ruleset. Fun to run, fun to play. Dare I start a thread with the proposition that d20modern IS 4E and we just haven't realized it? [chortle])
We do enjoy 3E; sometimes we gripe about its shortcomings (which have been well-discussed on these boards). House rules and Rule zero are our friends.
We do occasionally dust off our Moldvay Basic books and play old-school. Lots of fun, but we are reminded then of its shortcomings as well (also well-discussed on these boards).
No one but me in my group wants to play again using the hallowed original, stapled books from the first box set. They say I'm crazy to want to! Feh.
We talked about moving up to 3.5, but no one wanted to shell out the cash so soon after 3.0 - we did our homework on these boards and elsewhere and the changes/improvements in 3.5 weren't compelling enough to drive the purchase for us. YMMV and more power to you, friends!
I guess I'm in the same camp as Diaglo - I play 3E but my heart still belongs to the old school. (But I think I like 3E a wee bit more than Diaglo does!)
[Goes to dig up dog-eared copy of "Men & Magic" for a nostalgic read-through]