Dreamcast programming info and tools.
Given that these game consoles are
(a) apparently more readily hackable than PlayStations (for one, you can
make a bootable CD for them with a normal drive), (b) run NetBSD and Linux, and
(c) are discontinued (and thus likely to be selling cheaply, especially when
all the kids want a PS2), they may be worth buying for hack value. Now if
someone figured out a way of bolting an IDE hard disk onto one, it would make
quite a nifty web server/MP3 jukebox/(insert your own application here).