Tekken is pretty popular here from what I can tell. It the only 3D fighter people bring up.
Street Fighter is one of the most popular here in U.S.
One thing to keep in mind if not enough people there supporting the game it hard to get it to show.
Not sure how many DoA usually brings in tournaments but I assume around 30-40
The FGC mainly consists of Capcom fanboys. Also Capcom is a big sponsor for EVO, so its not surprising that SF4, SF x TK, UMVC3 is always at EVO. Still, I'd really like to see DOA make it to EVO one day.
From my experience there was only one player here in So Cal who actually tried to help out (or even talk to) newer/umfamiliar players here in So Cal. Everyone else just kind of kept to themselves. The DOA kommunity on the other hand wasn't like that.