Pages filled with bizarre notes that they more than likely won’t be able to decipher. Computer nuts experienced with *nixes could read some of them, but most wouldn’t be in near enough context for understanding.
Books. Lots and lots of books, arranged in ways only I’ve ever been able to understand. Programming and UNIX and poetry and science fiction and science and linguistics and books of strange facts. It looks like hell, but it makes sense to me. Nobody else, though.
Some poetry, both on disc in my desktop and hardcopy. All of it beat, but not half-bad, if I do say so myself. The poetry should be pretty self-explanatory. 
CDs. Many, mostly oldies and alternative and a goodly portion of punk. Not too bad, and better arranged than my books.
Some VHS tapes. The Trilogy (enhanced version), Clerks, Office Space, Fear and Loathing in Las Vegas, Plan 9 from Outer Space, M and Metropolis (both Fritz Lang films), Nosferatu (original version), Shadow of the Vampire, Alice (Jan Svenkmajer), and a lot of other movies, most of which I hardly watch.
On my desktop, a lot of programs I’ve downloaded, both for Linux and Windows ME. More for Linux, though, and nearly all of them gzipped (or, lately, bzipped) source tarballs. Emulators for machines as diverse as a Z80 running CP/M and the PDP-8. An Intel 4004 emulator with the source of the multiplication program I wrote for it (the Intel 4004 had no (documented) multiplication opcode), plus a listing, a flat binary, and a memory dump created from that code.
On my laptop, almost nothing. Little difference from my desktop in what it does have. (My laptop is an ancient Gateway machine running a first-generation Pentium (fdiv-bug free, though :)).)