AK suited or off-suit is a good drawing hand. Preflop you are ahead of all other Aces (AQ, AJ, A10), you have 6 outs against any pair outside of AA or KK, and you have a broadway draw. With AK you your winning percentage goes up when you see all 5 cards, (flop to river), since most of the time when you miss the flop (on a board containing no Ace or King) your hand essentially turns into a bluff.