I agree with the above post, I've been telling my friends who want to get a big iPod to wait, because if all the previous rumors of the full screen video iPods are worth two cents, this is how its gonna be done.
I think that basically we're looking at a thicker form factor than the iPhone (for now) and two sizes of iPod, 30-50 and 80-100 gigs respectively. I also think that with that tiny mac os x, they are gonna up the UI of the iPod to take advantage of that big beautiful touchscreen, and likewise will give it some basic PDA abilities off the bat, maybe iChat and Skype down the road. I certainly dont see them doing iChat and Skype right away, unless they add one key feature thats been previously rumored.
Bluetooth. If they do full bluetooth in this thing, we can finally get the wireless sync iPod, which i perosnally love. It also opens the possibility of Wi-Fi so you can do skype or iChat type apps at starbucks or something, but not absolutely everywhere. They cant go much further content wise, we have music, pictures and videos, but maybe, with the new screen and all, you can get basic versions of your RSS feeds inported to your iPod in the morning, and read them throughout the day using a notes type app. that would rock out loud. that also opens the idea of having books and newspapers and basically text based media on your iPod as well, and from there, the only way to get more content would be with the iPhone.
Because of that, I can see this being nearly the last iPod with really new features. After this, i just see it getting thinner with some updates here and there to the nano and shuffle. In the end though, I see all the iPods fading into the iPhone, the Video fading into the iPhone we've all seen, and the nano into something we have yet to see, and the shuffle, maybe that will hold on a little longer, but I dont see it lasting if the two pain iPods go iPhone.