I'm not going to bother listing Star Wars, since I think it goes without saying for all of us here. Though if I had to pick just one of the six, it would be ROTJ.
I have also limited myself to one each from the LOTR and Indy series so they don't completely take over.
The Big Lebowski
Indiana Jones & The Last Crusade
Kingdom of Heaven
LOTR: Return of the King Extended Edition