A bunch of text files containing random stuff, they'd probably be puzzled why I use text files to track budgets instead of something useful like Excel, a lot of nude photos of me and cute photos of me diapered... Oh and they'd also find a free computer.
I'm going to worship you.Music, lots of anime, an Nintendo DS emulator with Super Scribblenauts, school stuff, no naughty stuff (waste of computer space), old Skype conversations, oh, and a thread open on my browser labeled "If you died right now, what will they find on your computer? - Page 5".
They'd find an open console-based email client, as well as the cause of death:
"Looks like he was checking his email when he died."
"What was he reading?"
"I...geez! What is this!? Did the quadratic formula explode!? I see a 'teenage' in there... but it's being eaten... by some Linux or something."
And the compy would claim two additional souls.