I use Otterbox but I know someone with an Atomic Hybrid Composite case saw it for first time the other day its very light weight and durable.
Anyways I went to the website
http://www.atomiciphonecase.com
Looks like they are coming out with an even better model in 2 days called "The Diamondbach". Im going to hold out and see how this looks there isnt much info on it yet but if you go to that website its the 3rd flash picture on the screen.
The picture is just a sketch of it. I want to see actuall pics and a review first before I buy if its like the hybrid but better I will be looking forward to something new my otterbox is just to bulky for iPhone 4.