There was a CanSecWest conference this year, and one team successfully hacked into MacBooks. The were able to control the browser, and gain user controls. They attempted this on a 15" MacBook Pro because it didn't require them to have root access like the 17" did.
At least one of these two exploits remains unpatched, so you may still need to look out. ;)
Interview with Charlie Miller.Interview with Dino Dai Zovi.