Pirates of the Caribbean for me. All the way.
I love the original Star Wars trilogy, but the prequels tainted the franchise in my eyes.
I think The Lord of the Rings is a fabulous trilogy, but it doesn't have the re-watchablity factor that POTC does. Still, it's amazingly well made. Perhaps the best.
I greatly enjoyed all of the Spider-Man films, so that one's certainly up there.
I adored the first two X-Men, but The Last Stand disappointed me. I'm not a Superman fan, nor big on on Batman (though I like the original Batman and Batman Begins). I like original Trek, but I don't love it. Never been much for Terminator.
The Matrix is one I really need to go back and view again.