Originally Posted by Wilfred Laurier

Except for when riding on loose surfaces, the tire width is more important than tread pattern. If you want to hop curbs and snap fallen branches (and who doesn't?) then get some wider road tires (like 26X2.0 or so) which will also give a smoother ride over potholes and increase traction. If you can contain your enthusiasm for jumping off stuff, then a little narrower like 26X1.5 or so may be better. Knobby tires have no benefit - and in fact have less traction on pavement - compared to slicks or minimally treaded tires.