Shaman are the shit.  They're DPS machines.  Ive grouped for furnace with a 62 enhance shammy in outland blues/greens that did 45% of the damage in the group.  While that may not seem that good, we also had a 64 T2 mage and a 63 pvp geared rogue.  They shammy never pulled aggro off the tank, but he did OT when needed.