Hands down, without question, and it's not even close, is the Evutec Karbon Value. I am also a huge fan of ultra-thin cases, and this one not only is one of the thinnest I've ever seen, it has a carbon fiber look and a "smooth" carbon fiber feel that I haven't found on any other case, so virtually no fingerprints and good grip. Supposedly as strong as steel at 1/5 the weight. Here is the one I have as my daily driver, and only change it to something heavier if I'm going to be doing something a little heavier duty, like working outside or in the garage.
http://www.amazon.com/Evutec-Compati...mUvbUpU3210174