Kevin Federline

Ah, Kevin Federline, the deadbeat dad sent from Central Casting. He up and left his pregnant girlfriend, Shar Jackson, with whom he already had one child, for Britney Spears. (Yet when in parental competition with Britney, Kevin remarkably comes out on top. In 2007, Federline was granted sole physical custody of their two children. Just a few months later, Spears locked herself in a room with their younger son as a refusal to relinquish custody of the children. And then there was that whole head-shaving thing of hers, too.)