The Verdict, a movie about a drunken lawyer seeking redemption starring Paul Newman & Charlotte Rampling
Noi, a quirky funny film from a rather bleak part of Iceland
Auditon, a Japanese horror flick that'll get under your skin
Detroit 9000, blaxploitation film par excellence
Bill Cunningham New York as a unlikely fascinating documentary
Fellini's Roma for an insider's look at a great city
I even think Nacho Libre also qualifies as underrated.
Goodness, there's so many excellent underrated films out there.