Any comments on the City on Fire/Reservoir Dogs-Thing? You could argue that it's more a remake than a ripoff, but Tarantino still says that he didn't know the movie beforehand.
That's completely BS if he said it - he's an admitted huge fan of HK cinema, and borrowed numerous bits (visuals and occasional storytelling devices) from various HK films. However, the way they tell the basic story and the "lessons learned" are quite different in Reservoir Dogs than City on Fire. Some of this, I thought, had to do with Eastern VS Western conceptions of loyalty and honor. I don't think QT really did a disservice, and there are enough differences I wouldn't call it a straight up ripoff.
City on Fire actually isn't that great of a film, by the way. Some good acting, and a couple OK action scenes, but not much else. Reservoir Dogs is much better.
For an example that goes in the opposite direction, there's another Chow Yun-Fat film called Full Contact. It clearly is the same storyline as the 60s Lee Marvin flick Point Blank (later adapted again as the Mel Gibson vehicle Payback). Interestingly, ALL THREE films have a lot of their own merits. Once again, certain character fates differ - again because of different values about honor, loyalty and brotherhood. Full Contact is also an impressively grim film - worth checking out to contrast with the other two.
On a random note, the really awful 2001 film Head Over Heels almost shot for shot borrows a scene from From Beijing With Love. The Chinese film, in that case, is FAAAAR superior, and plot wise they don't have a lot in common.