Anyway. If the bike can fit them - which it probably can't - then the state of the art in dual purpose tyres are the Schwalbe Dureme and Extreme. The first is faster on the road, the second goes further off road. They use the same technology as the Supreme that has already been mentioned but with a more agressive tread pattern that gives better braking and cornering off road. See
http://www.bikeforums.net/showthread...res.-(meanwile!)