Sorry for the long subject line, I tried to cover all the topics that might be relevant.
I wrestled with a DVD 0704 install the last couple of days, the biggest problem (besides me) being that I couldn't get an external IP that wasn't assigned by the internal DHCP server. IOW, my external nic would get a 192.168.80.n IP, no matter what I did (like, reinstall, go to the Kubuntu Network Settings interface and alter settings, etc). I figured out how to hose the system, but that was the extent of my progress.
On a whim, I decided to turn OFF the DHCP server, update the network interfaces, and voila!, instant correct external IP.
Re-activate the DHCP server and everything starts working (updates, interfaces detection...the works!).
I was doing all of this from the browser screens.
My connection is LinuxMCE box internal nic ---> cable modem ---> internet.
Hope this helps someone else!