I just picked up the Seidio Innocase II Surface Case for HTC Evo 4G. Seidio is one of my two favorite manufacturers for mobile phone cases (Otterbox is the other, in case you were wondering). The Innocase II is exactly what I was looking -- it adds a nice layer of protection, gives the phone a tacky grip, and doesn't add any bulk to the phone. The extra tackiness is especially useful when holding the phone in landscape mode; it just feels much better in your hands thanks to the rubberized shell.