My thoughts:
Nano:
I think the Nano was fine the way it was and serving it's purpose. The new "Fatty" just looks bad and isn't worth the video option, especially considering the very limited memory which would only allow you to carry a small amount of video anyway. I guess I'll be one of the few enjoying buying a previous model on the cheap.
Classic:
Hey, why mess with a good thing? But, the Classic and Touch are 2 products that should be one.
Touch:
As said before, 2 products that need to be one. The thinness fixation is out of control. Just ask Kate Moss!! (I kid, I kid) Why can't Apple just put the micro-drive in the Touch which has a lot more memory and is much cheaper, GB per GB than flash. The end result would be a Touch with the memory of a Classic for the same price!
It's kind of obvious what's going on. Apple is taking a page from their own book. Think of how many additional sales of next gen iPods Apple made to people who already owned previous gen iPods. Apple capitalized on the slow growth of hard drive memory, and now their positioning themselves to ride that money train all over again with the Touch. Simple, but genius. We'll see intermittent upgrades in memory with just enough feature and style changes to get people to want to buy all over again.
My advice: outsmart the fox. Buy Apple stock and buy your next gen iPods with the almost guaranteed dividend checks!!