Purely for WHM duo/lowman, I like DRK/SAM RR+Sanguine Scythe+Impregnable Tower. Fat stack of HP for survivability, good crit rate and crit damage. You can drop Tower for VV or GH if you want more kill speed instead of 3k+ HP, but I'm usually #2 to a MNK who I'd rather let have hate for Counter tanking, so raw damage is less important.
Tower is extra nice for landing Stun a few extra times on mobs that have/build resistance and getting a little extra out of the rest of your magic. It's great to know a mob is Stun immune instead of wondering if you're just being resisted.