Adam Schmelzle:Do the files go across the local network or the internet to get to the Xbox?
The files go trhough the local network and actually my experience is that when both PC and XBOX are wired, the process is very quick. Also, when you are deploying your own game, only modified content is sent over the network on each build, so that makes the process still faster. You can even see how content is getting uploaded on the Game Studio Connect, and usually most of the files are sent in less than a second.
I bet this issue is related to your PC, you were probably running a VPN connection, a Peer to Peer software or something that was eating bandwidth a lot. I have experienced network problems when connected to my workplace trhough a VPN, I always have to disconnect the VPN before connecting to the XBOX 360 for XNA development, or just to use the Media Center extender functionality. This same problem applies to networked games when playing over a LAN, If some PC is connected to a VPN, it never finds the session.