I think the bottom line is that tread pattern doesn't matter for tires ridden on pavement, but it can matter for tires ridden off road. One way it matters for off road tires is that it can affect how well the tires shed mud and debris.
With that being said, I always go with the arrows, if there are any, road or mountain; but then again I line up the labels with the valve stems, too.
Last edited by well biked; 10-31-07 at 09:06 PM.