According to Cnet Review:
Design: The Nano 4G feels impossibly light and thin, with a seamless metal construction that prevents it from snapping like a twig. A slightly curved design gives the Nano 4G the essence of an airplane wing, repeating the rounded design themes of Apple's iPhone 3G and second-generation iPod Touch.
Apple always come up with a best seller, I believe this will be one of them. I will most probably buy one for my son after his SPM exam.