20. JaMarcus Russell – 2007 – Oakland Raiders

What a blunder. Aside from Ryan Leaf, the LSU star is arguably the biggest bust in NFL history. As a rookie, he signed a six-year, $68 million contract and didn’t deserve a dime. He battled weight issues along with multiple off-field problems and ended up playing just 31 games for the Oakland Raiders.
Source: SportsBlog, Huffington Post