Camerahacker wrote a post about netbooks from a media perspective.
I encourage people heading on over and check it out. It's a very good read. While I am sure netbooks are not made with mobile warriors who deal with media in mind, it would certain be something someone can consider designing one.
Consider that duo core Atom chips from Intel are on the way, there is likely enough power in those CPUs to power some photo editing and, at the minimum, allow SD video to be downloaded.
One thing I would like to add to CH's argument is the battery life. I think for a device to be consider a netbook, there ought to be a minimum battery life requirement. Say, 15 hours at the minmum? It is not an unreasonable number consider they are "netbooks" meant to satisfy 97% of all tasks mobile warriors do: e-mailing, web surfing, basic office work, etc.
And remember, aside from a small screen, there are Pentium caliber chips in some of these netbooks that can bench-press a lot of hefty tasks.
So, we ask for longer battery life and Firewire (even Sony's four-pin one would suffice). Anything else?
Note: Wired got the MSI Wind to run OS X which they find runs faster than XP. Take a look. Earlier attempts at installing OS X in Asus' EEE PC were successful if not for the lack of Wi-Fi access. Wired may have gotten Wi-Fi to work on their Wind.