7) Jermaine O'Neal
Definitely an unfulfilled talent guy. O'Neal blossomed in Indianapolis after entering the NBA as a teenager (not the only teenager on this list... hint hint) and being traded from the Trail Blazers to the Pacers. He's still around as well, playing for the Suns. He's only 34, but with his injury history there's no telling how many games O'Neal has left in the tank. Also, the second-best O'Neal of the last two decades, which is a definite strike against him.