Midnight Run, Midnight Cowboy, Some Like It Hot, The Big Lebowski(close call on that one as a buddy movie), The Producers(original) and Planes, Trains and Automobiles. I'm sure I'll think of more later.

Did anyone say Lethal Weapon? Love those guys.

OutOfContext - re: The Producers. Just have to say that I really missed the "Love Power" song in the remake. (Not that it would've saved the remake.)

Any of the Cornetto Trilogy - Shaun of the Dead, Hot Fuzz, The World's End and will extend that further to Paul (as all four had Simon Pegg as a co-writer).