I know a lot of people liked the minimalism of the now infamous Incase Rubber Sleeve...I bought an Agent 18 case this weekend at the Apple Store and I have to say, it's an excellent alternative. It covers basically the same amount (just over the chrome) with about the same bulk, but since it is plastic it won't stretch. And unlike some of the other plastic hard cases it is put on top/bottom, not front/back, which from my unscientific testing of the case without my iphone in it means it will be far less likely to pop open in the event of a drop.
