Hmm... Probably Kraft, because he's been the most successful. But, it's hard to say. All three franchises have pinched pennies at times. The Red Sox, for instance, sold off Mookie. The Patriots walked away from Tom Brady when he still had plenty left in the tank.
Give me Steve Balmer. He's not as obnoxious as Dan Gilbert or the Buss family, and he's willing to pay through the nose for a contender.