This topic might be a tough one. Although here are many great directors, but many of them have directed stinkers also (Spielberg in Jurassic Park II). So this might get little tricky

Some of my favorites are:

Peter Segal (Tommy Boy, Nutty Professor II). Very tight editing.

John Ford ( Mister Roberts, Stagecoach). Close o up of facial expression is his trademark.

Tim Burton (Ed Wood, Pee-Wee's Big Adventure).

Stanley Kubrick (The Shining, A Clockwork Orange).

Steven Spielberg. No explanations needed

Martin Scorsese (Taxi Driver, Goodfellas ).