Not underrated when they were released, but two movies I saw fairly recently that are probably underrated/not even seen by current younger generations would be The Graduate and Casablanca.
Casablanca was great, I thought it was some sappy romance movie but it was better than that imo. The Graduate was one of my favorite movies of all time. 'Nuff said.
Casablanca has really got a lot going on. That movie has aged better than just about everything from the pre-color era except perhaps M.
http://www.traileraddict.com/content...ics/bashir.jpg
http://www.youtube.com/watch?v=ylzO9vbEpPg
http://www.eorbit.net/~keith/movie/images/1016f.jpg
http://www.youtube.com/watch?v=ta1Sn6MtC9w
My favorite movie of all time, not completely underrated, but certainly not acknowledged enough:
http://i17.photobucket.com/albums/b8...WORKORANGE.jpg
http://www.youtube.com/watch?v=gmm5jeeH8mY&feature=fvst
A Clockwork Orange is a masterpiece. I think it is a must view.
A Clockwork Orange is underrated?
Not exactly, but it's surprising how many people have never heard of it. I feel like it's been buried away.
If you liked like Lock Stock & 2 Smoking Barrels, then you might like the New Zealand Movie called Stick Men.
IMDB: "Heavily influenced by Guy Richie's 'Lock, Stock and Two Smoking Barrels', with a similar plot (a few likeable lads get in over their heads with colourful local gangsters), style (slow-motion and other camera tricks, dark humour, some sexy violence) and setting (the seedier side a big city, particularly lots of bars), this is an enjoyable if shallow piece of pulp film. Like most Kiwi films some of the acting leaves a bit to be desired, none of the characters are particularly deep, you won't learn any higher truths or even move your intellect out of second gear, but it is good fun, particularly if you enjoy a bit of pool. Wait for the entrance of 'The Men In Black': it's the movie's best scene."
I remember watching it a few years ago, thought it was funny as hell lol. Not sure how well known if at all it is overseas.
How "Stay Tuned" or "License to Drive" have not been mentioned yet, I'll never know. Some of my other favorites like Death to Smoochy and Big Trouble in Little China have already been mentioned. Matchstick Men is probably my favorite Nicholas Cage movie not named Con Air. I haven't seen it in ages, but Big with Tom Hanks was one of my favorite movies growing up as well.
And for underappreciated horror before the whole series went to shit, Puppetmaster.