If you do jump into 3e, what I learned from helping people make the transition to it when it first came out: Approach it as if it is a new game. Don't assume anything you know about older editions applies to 3e.
With all the things that 3e did draw from the older games, it's easy to make assumptions; with all the things that changed, those assumptions are likely to be wrong. (^_^)
I'm guessing this advice is just as applicable to going from pre-2000-editions to 4e as well. (Heck, might even apply to 3e to 4e transitions.)
I also recommended that people play another game before jumping into 3e. For a couple of reasons: Putting something else in between can help with the advice above. Also, 3e draws from games other than D&D, so it can be good to know more than D&D if you haven't played other systems. I don't know how much any of that applies if you haven't been playing for a while.
Although, in general, I'd recommend you shop around. Don't just choose 3e or 4e because it has the D&D name. There are a lot of games out there that all have their strong and weak points and which support different styles of play. GURPS, World of Darkness, Fudge, Risus, Wushu, RuneQuest/BRP, the retro-clones, True20, Feng Shui, Savage Worlds, Microlite20, TriStat dX, vs. Monsters, and on and on and on.
