I like the BodyGlove snap-on case a lot.
Pros:
The belt clip seems to be very strong and is easy to use once you get used to it.
The case protects well but has holes in all the right places (speaker, camera, usb etc.).
Cons:
Some have said it interferes with typing. I haven't had any problem with that. I'm not sure what their problem is, but I thought I'd mention it since some claim this.
It is hard to remove. Some have damaged their phones trying to remove it, which I consider user error. I've removed mine about 6-7 times with no damage. You just have to be careful about which flanges you pull and in which order.
It prevents you from using the phone with the media and car docks.