Once Upon a Time in America (DVD, 2003, 2-Disc Set, Special Edition 229-Minute Version)
One of the greatest.
After watching The Good, The Bad, and The Ugly, I didn't ever think any other Leone movie can come close to that...but I was wrong. This is without a doubt one of my favorite movies. It's deep, depressing, uplifting, and even comedic. Watch this if you are into good movies.
One Flew Over the Cuckoos Nest (DVD, 2002, 2-Disc Set, Two Disc Special Edition)
This film is funny, heartwarming, and very sad. It's truely on of the greatest movies I have seen. I would highly recommend it to anyone.
Seven Samurai (DVD, 2006, 3-Disc Set)
If you haven't seen an Akira Kurosawa film, this is the perfect place to start. It's my favorite from him and very epic. Do not miss this one!