Speck ToughSkin for iPhone 3G
This case is designed to provide the ultimate protection for the iPhone 3G. The case in my opinion is somewhere between the protection offered by The Otterbox Defender and the PixelSkin.
The ToughSkin does a really good job of protecting the iPhone from drops, but if you compare this to the Otterbox Defender the defender obviously give better protection. Similar to the Otterbox all the buttons, such as sleep/wake, silent are accessible through the case. Also there is a special feature on this case, the bottom part of the case folds away allowing you to dock the iPhone with out removing the case.
In all this case provides good protection to your phone for a affordable price of $17.47.