I tend to be a squad leader type in games that have coordinated teamplay. I usually take the initiative when no one else will and try to lead by example, rather than by lecturing the other players before every game like I've seen some annoying micromanagers do.
I like all of the roles in the poll, though, and I'm good at most of them. My favourite role in Operation Flashpoint is that of a pilot. Helicopters are great, but the A10 is epic win once you become good at flying it, especially in FDF mod where it has nice new sounds, a working ejector seat, and a much more effective 30mm cannon.