I've played SWG, WoW, and WAR. My favorite out of those by far was SWG, but only for the first year it was out. After a while, once they changed it up a lot, it basically became a completely different game, just with the same theme. The level of involvement was amazing.
The player owned cities and player houses, the method of harvesting materials, and the fact that the entire economy was based off of player made items was pretty bad ass. Some fun as hell PvP in that game too.
Looking forward to SW: TOR coming out probably at the end of next year. That will be fuckin' epic. That is, if I even really have time to play. Senior year of college + staying in shape = Busy.