To be honest, I haven't caught much of Spike Lee's recent work, but I'm still a very big fan of School Daze, Do the Right Thing, He Got Game, Jungle Fever, and even Malcolm X.
As far as his Knicks fandom goes, I think it's entertaining in the way that Jack Nicholson is entertaining as the Lakers' resident celebrity fan.
He's good for the game. The more hateable he is on the side lines, the more fun Knicks games are (especially now that they've final got some aspirations).