Last time I bought a used 1e book from my LGS (a nice PHB IIRC), the elitist gamestore clerk literally said "Have fun with your THACO." I think he was trying to be funny and maybe even endearing, but he came off like a complete douche. There is an occasional C+C or Hackmaster tourney at that store, but I have yet to see any true 1e tourneys. If it's not a current or (better yet) brand new system, most of the folks there tend to scoff.
I tried to convince my group to play 1e, but they are, for the most part, hardcore WoWers and enjoy the customizable component of 3.5 (Feats, PrCs, etc). They don't want to go back to class-dependant skills only.
I, personally, solve this schism by just adapting whatever I want to whatever I'm playing. I collect great adventures and fluff from any game since adapting stuff to 3.5 is straightforward (though I usually don't trouble myself with a strict conversion ... that would be tedious but not impossible).
RE: 4E, if it can overlay transparently on top of 3.5 or even D20, I'd probably make the switch. I love my D20 library and have invested quite a bit into it. I feel like the current game is as strategic/wargamey as I'm willing to go, so if 4E becomes more mini/battle-driven and less about role-playing (like rumors suggest), I won't bother. To me, D&D at its best is a balanced union between roleplaying and combat, and if that's not reflected in 4E than I doubt I'll be playing. I'm sure I can convince my friends to play whatever edition of whatever game I want when it comes down to it, but I try to follow the advice of Robin Laws.