I have three cases for my phone: the incipio which is a gel covering encased in a hard case that protects the corners of the phone (where it will hit if dropped), the iFrogz because of the way it looks and disconnects easily, and the belt clip when I am at work or just in formal/business attire. I reccomend any of those.
And the invisi shield is a good product but be careful when using it with a docked car charger like the Belkin as it rips and tears the shield off the sides of your phone. Same goes for attempting to put cases on it. I tore off my shield off the side and back of the phone and just have it on the front.
AT&T has a new case out called the Otter Box. It's pretty much the most durable case out there right now, so check it... (continues)