You can trade in a pre-DVI PowerBook G4 (400, 500, 550, or 667 MHz ones) for $700 credit towards a new 15" or 17" PowerBook G4. That's pretty good for a 400 or 500 MHz one, not very good for a 550 or 667 MHz one though, you could probably get around $1000 or more for a 550 or 667.