I recognize this thread will be based on opinion and personal experience, but I'm curious to know what people think of various MMO communities. Here are my thoughts:
LOTRO - I can't think of a bad player experience in this game, and people always seemed very willing to help. Also, everyone seemed to respect the lore even if they didn't roleplay (ie, nobody running around with dumb legomyeggolas names.)
GW 2 - the open world event system I think encourages good cooperation and the holiday events bring people together in ways I haven't seen in other games. There's also a lot of server pride in WVW though rivalries can get ugly.
SWTOR - mostly ran into nice players but the solo nature of class stories made it hard to get groups.
As excited as I am for the expansion, almost every session I feel I run into more douchebaggery. Lots of killsteals at lower levels and PUGs are the worst. I know it's a great game if you have friends but the leveling process is really brutal thanks to elitist a-hats.