David Lynch-Don't really like his work but if I had to pick, Blue Velvet.
David Cronenberg-History of Violence
Lars Von Trier-None of them, can't even pick one I like. All come off as pretentious to me.
Steven Spielberg-Jaws or Raiders, love both equally.
Martin Scorsese-Goodfellas, greatest movie ever made, IMO.
Sam Raimi-The Gift
Guillermo Del Toro-Blade II
Johnathan Demme-Silence Of The Lambs
Wes Anderson-If I had to pick, Bottle Rocket. But his work strikes me as pretentious as well.
Alexander Payne-About Schmidt
Ridley Scott-Alien, one of the top 5 movies ever made.