I am almost always in offensive stance with a 2h Axe. I went with 2h Axe because when I hit 18 and saw the Tsang's axe, i wanted it
I have 0 problems with agro, and healers don't seem to get overworked (in most pugs, after we're done, they all praise me on what a good tank I am, so I'm assuming my damage in take is not too much for them).
Very rarely I'll whip out the sword and board and drop to def stance if my health is getting low and I don't see heal spells being cast in the group window (like when the healer LD'd mid pull or something). Or if we have no CC and I've gotta take being beaten by more than 2 or 3 4dots.
I'm 30 now and using the Ageless 2h Axe (it's insane).