For me, tanking is the most fun role in raids/heroics.
And healing is the least fun, although I was a main healer in classic wow raids.

I enjoy dps too, but not as much as tanking.

It is hard to not pick the druid.
Since they can tank and dps (Feral) and dual-spec (Resto).
And have a huge gathering advantage, not needing to unmount with Swift Flying Form.
I main tanked many Karazhan runs and off-tanked SSC/TK some, as a Druid.

My (Prot) Pally is a better tank.
Both in terms of gear and mechanics.
One button spam, as optimal threat for single targets and groups is hard to beat.

I've also raided on Disc Priest, Demo Warlock, Elemental Shaman and Combat Rogue.

I'd probably pick Druid too.