Ooh ooh ooh oooooooh! I've just discovered this thread, and quirky/underrated films are one of my big passions in life! I have a particular findness for French and Scandinavian films (the Danes and Swedes do great crime and thrillers), followed by Spanish. Also many English speaking ones. Here are some of my underrated favourites:
Friendship's Death (have been trying to find this on DVD or anything else for over 10 years now...)
Themroc (superb!)
Didier
Black Sheep
Angel-A
A Town Called Panic (the movie, not the series)
13 Tzameti
Belleville Rendez-Vous (Also known as the Triplets of Belleville)
Bubble Boy
Buffalo '66
The Castle (this was pretty mainstream in Australia though)
And I'm going to have to be the pariah here and say that I thought Gattaca was very silly and didn't enjoy it much at all. DESPITE Uma Thurman!
Gotta go feed Lars the Lamb. More later! ooooooooooh exciting thread! am going to look up some of those others mentioned.