Tough decision. It's tough to compare across the sports, because the Sox can spend with no real limitation, while the Celtics can't.
I respect the ownership of the Celts, Sox, and Patriots. All of them seem to provide their teams the financial resources they need, while at the same time backing off and letting their GMs / coaches do what they need to do.
Ultimately, I went with Bob Kraft. I don't like some of John Henry's "evil empire" crap, and I think he inserted himself too much, too publicly into the Texeira negotiations. Wyc also sometimes talks about things he doesn't really know about, and the "I was being Belichekian" stuff about KG's injury put me off.
Therefore, it's Kraft by default. He's got the most championships, and he saved the team from being moved. He's spent money when he needed to, but also trusted Belichek's judgment when franchise players needed to be moved. It's close, but I think he's probably the best of a very good bunch.