I just received a black Nano, and in my opinion the sound quality is better than my iPod Photo. Plus there's no pause when you skip songs like the other hard drive-based iPods
I got mine mainly for the form factor, so when I'll be commuting I'd have something smaller to put in my pocket. I love it though! It does tend to scratch easily, so the least anyone should do is get some protector for the screen. I'm not too worried about the body scratching, I just want to be able to read the screen.
And to the person who asked who has 5000 songs, well I have over 7000 now. I basically digitized my whole CD/record collection