Apple said the iPhone 4 was scratch-resistant. Well, Gdgt editor Ryan Block got a scratch on the iPhone 4 in normal daily use. Now you might say that Apple said that it was not scratch-proof, but scratch-resistant. However, they also say that it is "Chemically strengthened to be 20 times stiffer and 30 times harder than plastic," but this doesn't look good.
Well it might be more scratch resistant than the 3GS, but I wouldn't go throwing it around, or putting it in the same pocket as your keys as it can still scratch. Even on day one.