Ryan Lochte and Michael Phelps
Phelps vs. Lochte will be the water-cooler debate going into the London Olympics. The world's two best swimmers should go head to head in two events -- the 200-meter freestyle and the 200 individual medley. Phelps is the defending Olympic champion in both, but Lochte won both world titles this year, becoming the alpha male of the pool in the process. Phelps and his coach, Bob Bowman, feed on any form of motivation they can find. You can bet Phelps is reminded daily about those two losses at worlds, where Lochte needed two personal bests to win by a combined half-second. Phelps said he wasn't in peak shape at that meet, but we also don't know if Lochte has reached his limit yet.