I'm generally a big Tarantino fan, but I will admit that the Grindhouse shit wasn't that great, and Kill Bill seemed a lot cooler when it came out than it does now. Also, Kill Bill 2 was a real letdown. The bit he did in Sin City was wicked, though. And he's done some writing collaborations that were cool, like From Dusk Till Dawn and Natural Born Killers.
But I can't think of anything he's done really recently that was that good.