If you’ve ever wanted to set up a Mac for someone and do tasks such as preload applications or run Software Update, you’ll have to jump through the setup process, but the next user won’t be able to enter all their details. How can you go about resetting the Mac to re-run the Setup Assistant and give the new-Mac feel?
A tip I ran across on niload.com describes how to do just that. Basically, you run setup like normal, log in and do updates and/or install programs, then remove a few things and shut down. Upon reboot, the Mac will run the Setup Assistant as if it just came from the factory. You can read the full hint for the detailed instructions. (Also, note my comment at the bottom of the hint, as it should be a safer way of removing the account.)