Personally I think the Nano represents great value for money - however for the price of the 8gig version you can get a full blown 30gig video iPod - so I'm not sure I see the point, also it only seems to be available in black.
The other thing is the 1gig version, which I find most appealing due to my simplistic needs, has not been replaced as yet.
I'm struggling to see the point of the change though. It's still an iPod Nano, only it's shapped a bit differently. Is the screen less susceptible to scratches? Does the battery last a bit longer? I suppose new technology could benefit both those issues.
What would be cool is if the Nano incorporated the video feature of the larger iPods, but as it only has a 1.5 inch screen I can see why this hasn't been done.
The point of making it available in different colours? I'm not sure, because it still seems a bit flimsy to give to kids, the only "demographic" that would truly care what colour an mp3 player is. Whether the fact you can get it in blue, pink or green would convince those 3 people that don't like them enough to jump on the bandwagon seems somewhat unlikely.