Sorry, but every part of a render matters. It's about overall look, and unfortunately whenever I looked at that render I was rather distracted by the shadows to be perfectly honest. Once I got past that however, it was rather nice. ;)

Also tapion, that's nice...when most people use lathe NURBS their first time they have issues with sections going inside eachother. (Or do you have that issue on bottom? If you do, just make sure the vertical dimensions of your object's first and last points are equal. Also, you should only be placing points on two planes...probably X/Z and Y.)

Also, I would recommend creating textures when possible rather than playing with preset shaders...it will give you valuable experience. (Though don't get me wrong, sometimes for certain parts shader manpulation is the way to go!)