I've been through 3 cases. Here is my review on them:
1. Gray Case Mate - bulky, but provides the most protection. Came free of charge when I purchased the phone. Rubber areas near volume rocker become loose and start to pull away from phone. Makes phone to bulky for pockets.
2. Black Silicone case - $7.48 on Amazon. Slim, but not as tight a fit as could be. Picks up ever single piece of lint in your pocket, and is difficult to remove from your pocket.
3. Crystal Skin (Black) - $6.95 on Ebay. Very slim, very tight fitting. Made out of flexible plastic. Best case yet (and cheapest). Doesn't add any bulk, doesn't collect lint, easy to get phone in/out of pocket. Material feels pretty solid, so it might absord some of the shock should I drop the phone. Maybe not as much as the Case Mate...but hey..that's why I have the insurance.