it didn't take long for me to realize that the GSE XNA xbox 360 project forces a deployment to the xbox 360 when you debug or build. so how do you work on your xbox 360 game when you're in the coffee shop?
there doesn't seem to be any way to disable the deployment, so - unless you take your xbox with you - it's a bit of an issue. even adding Any CPU as an additional platform in the configuration manager didn't work. I found a forum post about debugging without the xbox 360, and it seems that the current solution is a bit of a hack:
"You can start a new Windows Game and link all the files from the 360 project. It would probably take about 30 seconds to set up. After you create the Windows Game project, right click on the project in the Solution Explorer, select Add Existing Item, select all the files in the dialog, click the arrow on the Add button and select Add As Link. Any changes made in either project will be reflected in the other."
there is a second solution in the post (manually altering the project file), but it isn't recommended.