Im assuming you take multiple genras?
for western action/comedy/pure epicness got to go with Tombstone(1993) movie is just balls to the wall awesome. Im not sure how many times ive seen it since i was a kid but it has never even gotten close to "old".
Star Wars(4-6). Some of the best sci-fi EVER. the force be with you.
Casino- What can i say, if George Carlin prays to Joe Pesci because of movies like this, you should probably check it out. Some good ol' fashioned american violence. mmmm
since someone hit Monty....
Blazing Saddles-One of the funniest movies ever made...holy hell i havent seen this movie in a year at least, time to go watch it. (ill post more later, seriously im going to go watch that movie now)