I saw the Nano at the Apple Store recently, very sleek and attractive. It looks way better than the white one. I bought a black one for my brother's birthday. I can't wait to give it to him!!!
If I was buying a Nano, I would definitely get black.
I would think that fingerprints would show up more easily on the black. It sort of looks like its made from material that's similar to the Motorola Razr. My friend has one of those and it looked shiny for the first day but now it's covered in fingerprints. Mind you I haven't actually seen the black iPod in person so I can't verify.
Of course you could always get a bunch of different cases for your iPod and then it can be whatever colour you want. That's what I did with mine (white).
I ordered a black nano, just got the notice today that it has been shipped! yee ha!! Ordered it through igive.com and went to the Apple store from there! It came with free name engraving and free shipping plus my charity also gets a percentage!
I ordered my Nano in black because I thought it looked sharp. I should have it any day now. Of course, I also ordered the 5-pack of "tubes", so it'll be covered anyway.