I played the beta of GW2 and it's great. I really like the idea of combining skills with other players to use new skills. I also like that players don't always have to form a holy trinity party.
Even though I'm itching to play it right now, I'm pretty sure there would be a lot of latency and patching issues due to the servers being overcrowded once it's out. So I'll control myself and let GW2 mature and age for a while.