I have to go with Caddyshack, one of the funniest and most quotable movies of all time. The characters are all great, my favorite being Judge Smails ever so closely followed by Al Cervik.
The funny thing is, I LOVE Caddyshack but am indifferent toward or dislike every other golf movie I've seen. Tin Cup annoyed me because Costner is Costner and Rene Russo has a jawline Kirk Douglas would envy. Bagger Vance the movie is a cartoon compared to the book. Greatest Game Ever Played feautured some truly uninspired acting. Gentleman's Game was close but ultimately hoaky and moralistic, despite a good performance by Gary Sinise.
When I think about it, I like like Caddyshack not only because it's hilarious but also because it captures an part of the game much better than the other movies. Though a comedy, it's portrayal of caddying and country club golf was, I thought, pretty authentic. I think anybody who's caddied at a club would agree. To me, what makes some of the best scenes so funny is how closely they mirror reality.
With all that said, Caddyshack 2 is the worst golf movie ever made, hands down, end of discussion. What a piece. How they managed cast Chevy Chase, Randy Quaid, and Dan Akroyd, and make a movie that stunk to extent it did, I'll never know.