I have the splash Vapor slim-fit case on mine. It does the job and it doesn't add much bulk to the phone. I am still trying to figure out if I am doing a screen protector or not. I tried the Zagg Invisible Shield and I did not like what it did to the screen. It certainly was not invisible. Some people don't mind it though. I am going to put a Steinhall Ultra Oleaphobic on my wife's phone tonight and see how that looks.
I looked at cases made by a company called Exovault, but I don't know how good they are. They are pretty expensive, but they have a few that look pretty cool. Just depends on taste and what you want to spend. Go to Exovault.com and see.
My wife and I went with the Otterbox Commuter while several friends went with the Defender. I moded mine some because I wanted a holster and kickstand. Posted pics in the iPhone4 cases thread.
I've had the Slider Case from Incase for 2 weeks and love it! Got it at Best Buy. Great feel! Easy in and out off pocket. Doesn't collect lint but isnt slippery either.
I can't post a link yet so just google Incase Slider Case
I have this one. Got it at vzw retail store. I love it...protective, holster & kickstand all in one. I cant post links due to post count......so copy paste...