I really like the Tech21 case I got from T-Mobile. It's thin, very snug, and has a good feel or grip.
It goes by various names; mine was branded T-Mobile but you may find the same thing under other names. Here's an Amazon link, and it's a fraction of what I paid for it. If the link doesn't work, look under Tech21, Impactology, or D30. 'Gel' is a little misleading in the description; the outside is a firm matte dense rubber-like material. It probably does make the buttons a little harder to push, but I like that.
http://www.amazon.com/dp/B00BE6R7J6/...pUvbUpU2236763