Well, lets see.

I can rip all my games onto my HDD so I don't have to use a disk ever again.

I can use my Xbox as a FTP or Telnet server

I can use the play any media file basically(video, music, image)

I can install Linux

I can use it as a emulator for all my favorite systems

I can use an xbox tunnel without without the use of my computer or gamespy

And did I mention a much bigger hard drive, or a allnew dashboard thats 100x better and customizable?

PLUS I CAN DO MUCH MUCH MORE!!!

Yay for Xbox.