To clear this up:

I have a firewall (Brickhouse(It's a gui for opperating the firewall in unix that ships with MACosX ))
I have checked for trojans,viruses and keyloggers.
I was on my computer when this happend and even if I was not my screen saver has a password and I ALWAYS start it when I leave the computer.
I'm on a home network with a dsl internet connection. (not sharing my harddrive or anything else for that matter)
My logs are gone. (deleted)
Some of my school papers are gone. (about 40 megs)
I unpluged my computer and changed all the passwords.

I'm wondering if an atacker leaves any other trace than what is stored in the logs?