Pulp Fiction was a fantastic film, stylish in every way when it came out. Reservior Dogs owns all though
Apart from films already mentioned I really enjoyed the Kill Bill duology as well as Death Proof.
His films express how Tarantino loves cinema. I do like Kill Bill as well, but get a bit confused by the black-and-white fight scene. It seems like a stylistic choice with the benefit to please the censors at first but then you realise that the scene exists in a colour version (released in Japan i think).