My brother-in-law bought four Xbox 360's last year on ebay. He managed to resell three of them for a high enough profit to pay for the fourth one.
PS3 and Wii are going to go crazy after this weekend. Personally, I plan on buying a Wii, but I have no problem waiting until I can find one in a store. I have too much stuff to do this weekend so I doubt I'll be able to pick one up on Sunday (assuming I could find one anyways).