360 Elite trade-in offer further clarified - Xbox 360 Fanboy
This post is mostly for my own reference. The above link is good information about Gamestop's trade-in for an Xbox 360 Elite. It's probably the route I will take, just so I can have a black Xbox and HDMI.
Some may just want the hard drive space. For half the price of Microsoft's paltry offering, you can hack up a WD SATA drive if you wish to use your own 120GB hard drive.
If I end up changing my mind at the last minute, because all my accessories are already white and component is doing just fine in 1080i for me, then I'll probably go the latter route.