I use a case and screen protector.
My case is the body glove. It's one of the bulkier types. It protects the camera pretty well (better than anything you'll find at a retail store, for sure)
Cheap little cases like Rocketfish (what bestbuy sells), or similar ones are, in my opinion, useless.
For a screen protector, I use one, I got mine from bestskinsever.
At least with mine, I've noticed that it gives the screen a bit more of a plastic feel, as it is plastic. Also, i noticed that if i had some moisture residue or anything on my fingers, it shows up more. It can be more noticeable. Smudges are more noticeable, but they can be removed pretty easily, especially if you've got a nice smooth cloth.
I'd say though, it's better to protect your phone at the cost of some of the aesthetics, than for it to get busted or have a scratched up screen.
Oh if you're new to it, you can find bestskinsever at
Cell Phone Skins & Protective Covers - iPhone Skins, Blackberry Skins, iPod Skins, Apple Laptop Skins - Best Skins Ever
For the body glove case, I found mine on amazon for $14 with shipping. As opposed to $30 on their site.
Bestskinsever screen protectors were about $6 each, and the more you buy the cheaper shipping is. I bought 3 and the shipping was free.