Mainly I play FFXI for my imersive MMO needs, but Guild Wars has long stood as my MMO of choice for speedy, casual play, and the place to go when I want a change of scenery. It's the only MMO I've played a lot other than FF.
I've always liked that you can get to end-game without too much effort and be able to enjoy the quests and areas of the game quickly, yet there's still plenty to do once you're at end game. It's a levelling model which works really well for the casual player. I've levelled a number of different characters to 20, and progressed with them through various story lines without getting bored. I loved that I could log on for 30 mins and achieve something - that's a lot harder on FF.
Started playing GW not long after it came out, but the slow pace of the orginal and the stark desolation of the Ascalon put me off and it got shelved. Bought the collectors edition of Factions the week it came out on a whim, and I was hooked immediately. Vibrant landscapes galore, good levelling and skill acquisition speed, and a superb well-ballance introduction area. I've since bought the entire series for my girlfriend too (who spends more time making characters than actually playing :P) and we have duod a load of content.
I have a lot of faith in the dev team, and can't wait for GW2. Quite a few of my friends plan to join me at release too, some who dabbled in GW1, some who are new. We all love the style of the art work, and I've always been impressed by the quality of the special events in GW - it always proved that the devs really cared about the game and wanted to keep it alive. We can expect more of that in 2 I'm sure :)
I still haven't decided on a race I'll start with, let alone a name :P