Rogue, for what may be obvious reasons. Failing that, a druid, priest or paladin so I could blow minds by curing people of what was thought to be incurable conditions/diseases/etc like cancer and AIDS, maybe get money out of it. Although druids would be pretty cool for the whole shape-shifting thing to get to places. Or I would be...
Actually, I better stop there before I just name every class and ways I would exploit their mechanics for the real world.