Oh Lord, I hadn't really thought about something like this until I saw some of the movies listed and realized how many of those I liked!
Movies I could watch anytime:
The Ten Commandments
The Poseidon Adventure
Field of Dreams (I get misty-eyed everytime I see the ending scene)
Dances With Wolves
Smokey & The Bandit (first one)
Any John Wayne movie (esp Chisum, True Grit, Rooster Cogburn)
Fistful of Dollars
Gone With The Wind
Philadelphia
Rocky I (the best one, IMO)
Star Wars Eps IV, V, VI, I, II (in that order)
Star Trek II, III, IV, VI, Generations
Somewhere In Time
Superman I
Blazing Saddles
Young Frankenstein