The silicon gel case sucks if you constantly remove the ipod from your pants pocket. The rubbery feel sucks. But it can absorb some falls on hardwood, and tile floor. That screen protector is a rip off. iTouch and many phones use a special plastic that was created in the '50s for its screens, it hasn't been used commercially til now. Basically it suppose to be more resistant to scratches and not crack easily. I've had my iTouch for 2 years and it has one scratch.
If you throw your keys and iPod in the same pocket then you'll be more prone to scratches.