Indeed, health won't make a real difference in end-game. Racials might, however.
A Draenei's GotN is actually good for a Holy Pally since it scales with +Heal. A Dwarf's Stoneskin can be nice for tanking, though I do not know to what extent. A Human's racials are somewhat trivial, in my opinion, as the reputation gains will be convenient for all races will eventually catch up anyway. BE's Mana Tap and Arcane Torrent is pretty nice and all, but anyway if you're rolling Horde you don't have any choice on the race. :P
All in all, go with looks first, and then racials if two races are at a tie.