Yeah, that's nice. This was news the day Leopard was released, along with the fact that you can submit cron jobs and reconfigure wireless. Guest Accounts are a good way to let your 9 year old use your computer. They aren't a kiosk solution.
I only ever use Guest mode with friends I trust. I'd let them use my account, but screen corners and funky shortcuts freak them out. The guest mode is a great way of giving people I trust a vanilla Mac to use for a few minutes.
Nothing says good web design like your snow/rain falling through the text making it annoying as hell to read. Turn that crap off.