I'm probably weird in that the movie I think is perfect isn't even on my favorite movie list: US Marshals.

The writing is amazingly clean and concise, it makes good use of conservation of detail and foreshadowing, the overall cinematography is clean and has no wasted/unnecessary footage that I've been able to see, the characters are easy to identify with, and it doesn't require you to bring knowledge of the genre or the previous movie with you into the show to enjoy it. It's simply one of the best executed movies I've ever seen, and I rarely like cop movies.

Sadly, I find all of my favorite movies are quite flawed when I judge their technical execution. I'd love to get to list a few more here, but I can think of mistakes and flaws in all of them. (I like B-movies, so that's to be expected, really.)