If this is going to turn into an MMO thread, let's all just be honest with each other.
I played Guild Wars for a little while. It wasn't too interesting to me. For a game so centered on PvP, the PvP itself was so...slow. I played World of Warcraft for about a year and a half a few years ago, and I thought it was a far superior game. Better PvE for sure, and after they added Battlegrounds, it had a better PvP offering than Guild Wars.
By the way, do NOT play World of Warcraft if you value your social life, grades, etc etc. I went to college for two years at a community college then took a year off to work and save up money before transferring to a four-year school. I was single at the time and my friends had all moved away, so I felt I could justify the huge time investment. I quit when I moved into the four-year school because it would have been socially, academically and romantically crippling to play at school. I'm really glad I made that choice.