Custom hard drive, MAJOR pain in the donkey. Sure the getting it to work part is fine, but the moving your saves over part
... *dies*
Edit: I got it working, found out the solution was so much more simpler than I could have thought. I just reformatted the dang thing in my xbox 360 and that made everything "work" correctly on the computer, I would also totally recommend Datel's Xport360 program, friggin awesome for game saves and transferring files