I would look towards getting a maxtor drive. I got a 300 gig one with 16 meg cache for under $90, It's worth the extra bread.
www.outpost.com or
www.directron.com
Also, I would look at softmodding your box instead of spending money on a mod chip. It would save you about $50.
Gamestop xbox used $100
Hard Drive $90
total Cost Under $200. Good luck, and if you need help with a softmod, let me know. I'll be glad to help. I can even do it for you. I'm listed here:
http://www.xbox-linux.org/wiki/Users_Help_Users
there are also a lot of other people on there who will also do it for free. (or a small donation) see page for details.