Goodfellas (considering a good bit of it was improvised)
Good Will Hunting
every PT Anderson film
The Deer Hunter
The Wrestler
Sideways
Lost in Translation
Up in the Air
BQ- haven't seen it
BQ2- Rescue Me comes to mind. The first 3 seasons (especially #1) were all brilliant
and to answer your Cannes question:
The Master
Killing Them Softly
Not Fade Away
To Rome With Love
The Place Beyond the Pines
Cosmopolis