They need to enable streaming from iTunes on a local network, both audio and video.
This would make a HUGE difference for me... I could likely deal with even 8gb's on the go as long as I could instantly stream up any video content off my Mac while at home. (I still want a 16gb, though. )
I suppose even if they don't make this an official feature, turning on personal web server and writing up a quick script that creates a simple html index page of your whole iTunes library would work just as well. In fact, I bet someone will whip up a little application to do just that if Apple doesn't beat them to it.
All this Touch talk makes me want one more... must hold off until they AT LEAST hit the refurb store, if not a price drop AND refurb.