Graal Online
Ragnarok Online
Final Fantasy XI (for roughly 8 years)
Everquest II
World of Warcraft
Guild Wars
Myst Online (Uru Live)
Lord of the Rings Online
Aion
Final Fantasy XIV

I try and stick with things as long as possible and avoid jumping around, but in some cases I just have to jump. My favourite MMO being FFXI.

I'm looking forward to Guild Wars 2, Blade & Soul and patch 1.9 / 1.20 for FFXIV.