Anyone but Jon Snow. Such an ending would completely ruin ASOIAF for me...
Preferably noone from House Stark or Targaryen at all actually, as I think that would be too predictable (although I would be more satisfied with the latter than the former).
Haha, IKR??
People are rooting for Jon Snow & Daenerys, but IMO, it'd be super lame if any of them get the throne.