fwiw, my iBook (only in white) shows wear on my heavily used keys and on the side of the touchpad where i use it to scroll. at various angles u can see it both bc of the wear on the surface but also from the natural oils which are likely accrued there from my fingers. i currently have (toshiba) and have had dark notebooks where the same thing occurs. imo it's just to be expected with a notebook if u have it for long enough. regarding the rest of the notebook, apple went with the matte coating for the black mackbooks, to specifically avoid the finger print issues that are prevalent on the glossy black iPods. on the white macbooks u'll end up w/ smudges every now and again which u can usually just wipe off w/ your finger, but the point being that dark smudges will show up more readily on white when u do get them.
my old roommate had a toshiba notebook as his only computer and since he was in grad school for a number of years almost all of his letter keys were not only glossy, but most of the letters were actually worn down! like i said, it's just part of computing, desktop or notebook. if you're really that anal about it regardless of what you buy, you could just buy a new KB to install down the road when they get too worn down for your tastes. OKAY!!!??????