I suppose I'm all of them - I don't have a preference for any given style and I'll use whatever tactic seems to be most effective in the situation I'm currently in. Large open level? Sniper. Small built up level? Ambusher. Enemy holed up in defence? Flanker. Enemy uncoordinated? Rusher. Every tactic has a time and a place.
In an effort to give a solid answer however, my default class in most games is usually equipped with an assualt rifle and a shotgun, and I'll tend to make building clearance my priority, so that would make me a kind of Pointman.