What are you guys talking about? What does it mean to manage content? I'm interested in this
If you are using XNA and want to target the 360, you have to work within the constraints of their content pipeline. The jist of it is since the 360 only runs the .net Compact Framework, it does not have access to the same classes that you take for granted on Windows to load various file formats (images formats, sounds, etc). To solve this problem (AFAIK, most professional games have similar systems in place to boil data down to a format suitable for the consoles), you place your content in the project's solution and when you build the project it builds the content as well into a generic format usable on both the 360 and Windows.
Managing content is still a pretty big problem. I simplified things a bit by having a set variety of tilesets or sprites you can choose from, instead of just importing any tilesets. It's not very elaborate, but it does work for what I need the editor to do.
Yea, I've been trying to enable the user to import any generic tileset. My current solution is to have the editor open the content project and update it when a new asset is imported. I have a feeling this may cause things to get out of sync at some point, but it seems to be okay for the time being.