I have this case as well, which is the
Best Buy Rocketfish Soft Gel TPU Fitted Case, color smoke.
This is a soft case, translucent with a glossy finish.
I bought it because 1) my favorite iPhone 3GS case was the
iSkin Solo, and 2) it was one of the few cases available before iPhone 4 release day.
Here are a few more pics:
It's a translucent case so the back lets the Apple logo show through. The inside has a bubble-like texture, not sure if that helps with drop protection.
As coasterider mentioned, the fit is great all the way around except for a little too much give on the lower right side (you can see it in the second photo from the top). I thought I had a defective case, but when I went back to Best Buy to exchange it, the replacement case also had the same issue. It's not super noticeable, but it's definitely there.
Other than that, the cut-outs and buttons are pretty accurate.
I went back to Best Buy yesterday and noticed they have a few more colors -- pink, a turquoise blue, and a dark blue.