I'm almost postive we'll see a 64GB iPod touch.
We might also see an all-flash Classic perhaps? That would definately make it thinner and lighter. Plus, they might be able to shove 128GB of Flash into a classic, yet keep it at the same pricepoint as it doesn't have the expensive touchscreen like the touch. Who knows, I'm just speculating.
I'm not even in the market for another iPod, but I would love the entire line to transition to nothing but flash memory
I truly think this is the way all memory will go in the not too distant future. I think that spinning platters of memory will go the way that spinning platters of vinyl went, into virtual obsolesce. That said, we're still probably at least 4-6 years away from flash memory that we can talk about in the terabyte realm.