I don't have to consider this one for even a second.
The Thin Man - 1934
More accurately all of The Thin Man movies. These are hands down my favorite movies of all time. I first saw these movies when I was maybe 13 and even then I knew that these guys were awesome. I totally wanted to have a marriage like theirs when I grew up!
William Powell and Myrna Loy are the best on screen couple ever. Period.
I've recently heard rumors about Johnny Depp doing a remake of the movie. Whether that will come to fruition - or when - I have no idea. But it could be cool!
Pirates of Penzance - 1983
I've seen this live twice, but nothing is as good as the movie... I mean Kevin Kline alone would be good reason for that! Also I love that my boys love this, and Matthew is currently trying to perfect the Pirate King's moves (from this video) ...this is also his favorite song from the movie. He thinks it's hilarious the way they are singing at the top of their lungs about how silent they are. Glad to see my 4 year old gets it!