Deschain,
Thank heavens that people like you are trolling forums late at night to let someone who is in a bad situation know that you wouldn't ever make that sort of mistake. Not sure what macrumors would do without you.
To the OP, sadly if you have lost the laptop your options are few, your files, passwords, pictures, transcripts are all out there in someone else's hands.
The most important thing would be figuring out what was there that you CAN change. Bank passwords, credit card login information, even forum access. Anything that may have been saved in your keychain. Change that information as soon as you possibly can. You may also call your financial service providers (banks, Credit cards, etc). Let them know what has happened and to notify you immediately of transfers or charges that happen on your accounts.
If you are a gamer, change your passwords to your accounts. The keychain is the most crucial information on your entire system that someone who gets ahold of your machine can gain access to.
Sadly, as most of us do, you probably have personal and confidential imagery/information on your laptop that is now in someone else's hands and you have to learn to live with the violation that causes.
Things like this do happen on occasion, and like any theft (assuming it was stolen) you feel very violated.
Hope you find it, sometimes things turn up or you left it somewhere and an honest person happened by who will contact you.