Hmm...Lets see

Star Wars Triology (original three)
Fried Green Tomatoes
Lord of the Rings Trilogy
Indiana Jones Trilogy
Monty Python's Holy Grail

I can't really think of anything else. Those are all the ones i have DVDs of. I never buy DVDs because once I have seen a movie in the theater i don't really feel the need to have it at home. What few DVDs i do have, some of them have never been opened (and are several years old). So I guess if i actually bought the DVD (even if i have never opened it) that would make it one of my favorites.