Hands down the coolest, most memorable character Quentin Tarantino has created yet. You only need to see Pulp Fiction once to be able to recite Jules' slickly-worded sonning of Bret and his boys. His pop-culture referential game is ridiculous (Ringo, Flock of Seagulls). Hell, Jules even cites a bible passage before he kills a guy.
And just in case you didn't know that he was one already, he has "BAD MOTHERFUCKER" stamped on his wallet. That's to say nothing of he and partner Vincent's (John Travolta) hilarious Jerry-and-George type banter that could fill a feature film on its own.