I've just got a new iPhone 3GS and trying to find a case for it. I am a bit clumsy, so wanted a robust, but stylish case. I came across this in Amazon. The RRP is stated as £14.99, but Play.com also have this for £10.99. As I have the white iPhone, I have opted for this. The black version costs £8.10 from Amazon.
I know that this is a bit chunky, and I could probably buy something cheaper and similar from Ebay, but preferred a branded product with the added 12 month guarantee.