I'd have to agree with WoW

For worst I'd say Halo 3 or MW2

Any game that involves guns usually has a TERRIBLE community. That being said, the best community I've seen is is Team Fortress 2. They're really competitive, but they know that it's a game and supposed to be fun, and can take failure with grace.

I also want to nominate the older FPS games. UT and Quake had awesome communities. There was rarely any talk during a match, since you would probably die if you did, and outside of the random hacking accusations at the end of the round everyone was almost always very very nice. Their forums are even better. The times that I played with assholes I can count on my fingers while in those games. Meanwhile i get on LIVE and I can't click a button without having some idiot bitch about it.

Now that I think about it more, the silent ones always kicked serious amounts of ass and seemed like jolly people afterwards. The assholes and the ones that bitched were always in the lower half of the scores. I guess they just went to play more noobish games like CS. I know that the CS community was absolutely full of assholes and people that just blew, the silent ones were either at the bottom or at the very top as well however. Then I guess all those noobs form CS went on to plague Halo when it came out and the LIVE community went downhill from there.

Barrens Chat: WoW

Where's Mankirk's wife?

Demon's Souls community is really dang nice....wait...they're all mutes.

Under the bridge, where all trolls belong.

WoW is one of the worse communities honestly.. it's basically made the game unplayable.
You must of been very lucky.

For the best community, I'd say Final Fantasy XI and soon to be XIV.

I found Schthack's Phantasy Star Online: Blue Burst community to be the kindest.

I agree FFXI was damn nice, you would occasionally get the standard dickhead, but far less often then most games.