I often find myself reflexively squeezing the mouse when I'm on Windows, and then experiencing disappointment when Expose doesn't kick in. "Oh yeah, I have to use the stupid task bar."
The Parental Controls should be on the radar of family folks looking for a new home computer. It’s quite robust, considering that it is built into the operating system. For that same reason, it should be MUCH harder for children to get around than third-party programs. Well, unless your kids can hack a root account.