I think I've played most of them.
Asheron's Call 1 - My first mmorpg. It was very innovative and fun to play. The evolving storyline kept me playing for 2 years.
Asheron's Call 2 - Total opposite of AC1. Best graphics I've ever seen but zero gameplay value.
Star Wars Galaxies - Became a super crafter and supplied half my server in medical supplies. Once I started putting in 40+ hour weeks for just crafting I had to quit.
Anarchy Online - Played at release but so buggy I quit.
City of Heroes - Hella fun game. Just too shallow.
World of Warcraft - Nice game, but bores me to tears.
Everquest 2 - I don't like games with forced grouping.
Guild Wars - Great game, but pvp felt meaningless.
Eve Online (currently playing this one) - Wildly innovative. Set in space, the game is simply ruthless. PvP is non-consensual and death means the loss of your spaceship which can be quite costly.
I can go on and on about how awesome this game is, but instead check out,
http://ccp.vo.llnwd.net/o2/video/2/EVEN ... sLarge.wmv
http://ccp.vo.llnwd.net/o2/video/2/EVEN ... sSmall.wmv
(smaller, lower resolution)