I just put a 250 GB hard drive in my xbox cos I had filled up the 120 I put in there when I first installed my mod chip. I found a program made by Avalaunch called Net Prepare. OMG what a great program. I just created a shared folder on my PC hard drive and then FTP'd to the Xbox and copied the C:\ , E:\ and F:\ folders from my Xbox into that shareed folder on my PC. Then I put the new 250 GB drive into my xbox and put Net Prepare on a disk, pointed it to that shared folder on my PC and BAM, it set it all up. Everything works exactly as before (including all my game saves which are still in tact), except now I've got 130 GB free space.
Recommended.