Top 2 that I've seen millions of times and will see a million more times without complaint are
1. Grease
2. The Outsiders
Other movies that I love and will watch over and over
1. Natural Born Killers
2. Pulp Fiction
3. Otto Up With Dead People (very weird movie. I don't recommend it unless you like weird, gross, and aren't homophobic)
4. But I'm a cheerleader
5. A Dirty Shame
6. Bound
I'm sure there's tons others that I can't think of right now.