Definetly
The American Astronaut. Still my favorite US film of the past ten years. Excellent example what you can do with a minimal budget. Special interest to head-fi'ers, since it's a musical
Too bad it's pretty hard to find now, the DVD has been out of print for a while now, although you might be able to get it directly from their site.
Another small scale US short film is
A short film about John Bolton, directed by Neil Gaiman nonetheless.
I would class some of the films mentioned here as at least decently known, such as Oldboy, Spring, summer... and Koyaanisqatsi, but that may be because I like to watch even
more obscure films and it probably is better to stick to films that people
can actually get a hold of on DVD or something
I'll list a few that I think have had low coverage in their own countries and/or abroad - or ones that I just think deserve to be seen:
A Stranger of Mine A very good, but less known Japanese film with no name actors
The Dish Small drama-comedy from Australia
Ritual Arthouse to the max!
Missing Pages You can view this visually interesting film online
Electric Dragon 80.000V Another film that head-fi'ers might like
Mind Game Wild animation
Sons Fantastic Singaporean short film
Angel's Egg Arthouse(ish) animation
Yûkoku Starring and directed by Yukio Mishima
... and many more! There's a huge selection of obscure films around the world and I enjoy finding them as much as finding a band or a piece of good music.