A few more underrated films would have to include:
Fearless-Peter Weir
La Roue-Abel Gance
Schizopolis-Steven Soderbergh (Yeah, that's right)
The Heiress-William Wyler
The Stars Look Down-Carol Reed
The Hudsucker Proxy-Coen Brothers
Vampyr-Carl Dreyer
Umberto D-Vittorio De Sica
Babette's Feast-Gabriel Axel
The Marquis Of O-Eric Rohmer