AD&D (Krynn, Greyhawk) - I've been playing D&D for like twelve years. While I was a diehard D&D 2nd ed person for ages, I've really grown to love D&D 3E. I've played in countless campaigns of both, and even run two. Krynn would be my favorite world, although nobody plays it anymore. I was in a long Greyhawk campaign before I moved to Seattle (like 3 years), and think it's also way cool. Forgotten Realms had some great novels but the world isn't as interesting to me, unless you count dark elves. My favorite 3E campaign so far was where we played our own home-grown ninja clan, though. *shrug*
Oh yeah, and I collect dice.