Double Draw Poker

Alright, a bit of an unusual puzzle this time, but I thought it was sort of neat. I first found this on the xkcd forums:

Alice and Bob are going to play a poker variant. A standard 52 card deck is laid out face up in front of them. Alice goes first, and gets to select any 5 cards from the deck. Then Bob gets to select any 5 cards that are still in the deck (not being allowed to select any cards Alice selected). Then Alice may discard any of her cards and replace them with cards still in the deck (discarded cards are removed from the game and do not return to the deck). Then Bob may discard any of his cards and replace them with cards from the deck. At this point, the game ends and whoever has the better poker hand of 5 cards wins. If both players have equal ranked hands, then Bob wins the game (that being the compensation for going second). Who wins this game when played optimally?

If you don't know the rankings of poker hands, you are beyond help. I guess you could look them up, but I actually would say you won't find this puzzle even slightly interesting so don't even bother.