Nate Silver breaks down clutch hitting in another excerpt from the "Baseball Between the Numbers: Why Everything You Know About the Game is Wrong" book:
Baseball is a game that is won by exploiting small advantages over the long haul. Certainly clutch hitting may exist in the classic sense of the term, but a lot of what we think of as clutch hitting may really be situational hitting. In some sense, the answer to the question of who the best clutch hitters are is that they're usually just the best hitters, period.
It is interesting to see that there are three players in the top 10 of the clutch hitters list that were drafted by the Twins: Kent Hrbek (4th), Matt Lawton (5th), and Kirby Puckett (9th). Only 10 of the players in the top 25 are currently playing, and no two of them are on the same team. Seems like you could work some Billy Beane magic and get all the great clutch hitters on the same team and magically win every game, no?