[cubicle67]

To expand; System Preferences > Time Machine will tell you time of last backup, date of oldest backup, etc. You email address will be in the Account settings of Mail (Preferences > Accounts)

Also available are - your home address and phone number (in Address Book, he'll already know your name from Mail), saved passwords in FireFox (stored as plain text), iTunes account if you've set it to save your password, and websites where you've set 'Remember Me' (GMail and the like) etc

Luckily for you this person seems to have some degree of respect for your data, and hopefully your privacy. If you're not happy with their access to this, it seems they have more leverage over you than you do over them.

Protip: In OSX you can set it to require login password after a certain timeout, eg 1 hour. It's under System Preferences > Security > General

[kabuks]

That's what's puzzling to me. I have it set require login everytime it sleeps. Somehow this guy got passed this