Havent really bothered with a screen protector tbh mate, the n95 screen seems to be pretty resilient towards scratches etc...think it has a non scratchable screen but dont quote me on that.
Case wise??, i bought the official nokia one, CP191 is the model of it....only cost me £10 and keeps my n95 nice and protected...it has a hole in the back so you can still use the camera if you wish.