I got an Otterbox for my Dell Streak. When I ordered my Streak from Dell they had the Impact series from Otter Box available as an accessory (the entry level case for that smart phone) and it has worked well for me. Being the tightwad that I am (and proud of it, BTW), I only recently moved to a smartphone but wanted to protect it without paying monthly insurance.
I think that some kind of protective case is a requirement for a smartphone. Otter Box has three levels of cases (Impact, Commuter, and Defender). My Impact was $20 and the Defender is around $50. The higher the price the greater the protection.
My Impact case is black rubber-type material that stretches easily around my Streak and allows easy access to all hook-ups, buttons, and sensors. It doesn't pick up lint. It does add a little bit of thickness for the blue jean pocket but it's worth it.
I think all the Otter Boxes come with a clear thin screen protector that can be stuck to the screen to protect it from scratches. Even though my Streak has Gorilla Glass I still like the idea of the extra protection.
Otter Boxes are available for any given smart phone and are custom made to fit perfectly. I'm very high on them and would recommend them.
Bama ED
PS-my Streak has a 5-inch diagonal screen which is large enough to load full internet screens (and not mobile versions of said screens) so I love my Streak.