(Older post, but I'll add to it for future readers' benefit)
The N810's front and back panels are aluminum, I believe, and are hard to scratch (at least, unless you're trying :P). The side edges are plastic, and will scratch. I dropped mine from waist-height onto concrete (>_<) and got two deep-ish scratches on the edges, but nothing else was damaged or disfigured. (I may have been lucky, though - I've since learned to unplug the earbuds before taking it out of my belt-case, as the cord tends to snag)