Apple has said it has "ideas" about how to make a better netbook, so we know it's at least on management's minds. Whether this is it, who knows. But if it is, based on previous Apple exec comments it won't compete with inexpensive netbooks, i.e., it will cost significantly more than the typical $299-399.
I'm guessing somewhere in the $799-999 range, but it will have a true C2D, not a wimpy Atom. It would also probably mean the end of the MBA and lowend MB lines. I don't think Apple can support 4 different laptop lines. It's too confusing for consumers.
I'd be in line for a basic low powered C2D 2.0+ tablet/netbook/subnote MB if Apple can keep it under $1000. As long as it has a real keyboard, BT/802.11n, 5+ hrs *real* battery life/and 60GB+ SATA 2.5" SSD I'm happy.
I doubt they'd drop the macbook no matter what they may release in the future. The macbook line is the main apple purchase for students apart from ipods.