Mind you this is over 13 years.
Combat Theater - now AvA and practically abandoned:
325th Checkertails
JG3
JG54
VF-27
Main Arena
JG3
Hells Angels - Loved that squad. A bunch of awesome guys and I miss them.
AoM - Hell of a fun bunch to fly with. And has some of the best pilots in the game. Not into bombing, or GVing though some do occasionally. No scorewhoring, Hoing, running. Just there for a fight. If you survive, great. If you die oh well. As long as it was a good fight.