Besides a dozen or so computers and consoles, the few main things I collect are guitars (along with assorted gear (I love my Takamine gx-100 explorer the most)), movies (dvd, hd-dvd, bluray), games (amiga, megadrive, ps2, pc, and xb360 mostly, but a few other assorted machines), and books (shedloads of computer reference books on most subjects spanning from c64 to amiga to pc (old and new), but probably 75% are novels. King, Koontz, and Laymon feature pretty heavily amongst my collection although Ive recently started enjoying James Patterson and others like Brian Keene.
Shame, but reading seems to be a bit of a dying artform these days (or maybe Ive only just tarted to realise what a niche reading for entertainment is, not sure which).