Star Wars as a favorite.
Under the radar is tougher...so many good ones and what qualifies as UtR? I mean, are Kevin Smith movies UtR? Probably not with this crowd, but to the general public. I saw Charade mentioned as a favorite above, but I'm not sure how many have seen it in this day and age. Does the cheese of Flash Gordon qualify? Then there some movies that made good money but maybe underrated with how much money comic book movies are making- I think Sin City is awesome, and Watchmen underrated because I don't think it ever could satisfy all expectations. Moulin Rouge is a great musical if you're ok with melodramatic camp. But I guess if I'm going to try and stick with one that people go "WHA?" on, I'd say Shall We Dance? The original Japanese version, not that Jennifer Lopez remake nonsense. I love that movie.