I picked ten movies that I truly loved, and it's hard to rank them in any particular order, but I'll give it a try:
The Dark Knight. Absolutely fantastic movie, I watch it whenever I'm able.
Full Metal Jacket. I've read the book this was based on, and I think they did a pretty good job adapting it to the screen (even though I felt the book was better).
Scent of a Woman. Al Pacino really shines in this film, I must watch it again.
The Breakfast Club. All I can say is, I regret not seeing this when it first came out in theaters.
Apollo 13. Historical drama done exceptionally well. I was a bit young to remember the actual event.
Crimson Tide. A heck of a ride from start to finish.
Down Periscope. It may be low humor, but I still love it.
Chicken Run. Good, fun movie.
The Replacements. Had some very funny moments.
Young Frankenstein. Classic Mel Brooks movie, and a great spoof of the horror genre in general.
There's a lot more that I like, but these are my big ten picks. The order can change depending on my mood, so take this ranking with a grain of salt.