Among movies he directed: 1. Pulp Fiction (no doubt) 2. Kill Bill (need to see it again to see if it deserves the spot above RD, I am lumping the two volumes together) 3. Reservoir Dogs 4. Death Proof 5. Jackie Brown
I don't really remember Four Rooms, but didn't he only do one of the four parts? And I'm not counting Sin City (which is one of my favorite movies ever, after Pulp Fiction) since he only directed a little bit).
Adding movies he wrote (Natural Born Killers, True Romance, From Dusk Til Dawn): 1. Pulp Fiction (always # 1) 2. Kill Bill 3. Natural Born Killers (hard to put this third, I love this movie) 4. Reservoir Dogs 5. True Romance 6. Death Proof 7. Jackie Brown (though the writing is better than Death Proof, I probably enjoyed DP more as an overall movie) 8. From Dusk Til Dawn
These are ranked by how much I love the movies, and not based on the writing alone.