Clearing your cache is a good idea, but someone brought up an issue in one of THE OTHER THREADS ABOUT THIS ALREADY...
And that is, if you downloaded updates for games off of Xbox Live, and are now without the internet for whatever reason, when you clear your cache, you lose those updates and the only way to get them back is to find a way to connece your 360 to the internet.
Definitely something for people like me to consider, as I will be connected to XBL when New Vegas gets here, but shortly afterwards, I will be without the internet for several weeks.