Bicycle Mechanics - Question about tire mounting with a directinal tread.

My tires have a directional tread (see photo).

I'm assuming the tire gets mounted so the tread lines point in the direction of travel as shown?

Yes, anytime there is any semblance of a v shape to the tread, it's usually recommended (by the tire manufacturer) that the tire be mounted so that the point of the v goes forward. In reality, on road tires, it doesn't make much or any difference, although with a more pronounced tread pattern such as the one you have there, I would definitely go with the v facing forward. I also think of it kind of like mounting the tire with the label lining up with the valve stem, i.e., mounting the tire in the recommended direction shows attention to detail.

With mountain bike tires, which of course have more elaborate and pronounced tread patterns than road tires, you'll sometimes see one direction arrow on the tire labeled for the "speed" direction, and one for "traction." Sometimes, a mfr. will recommend, with the same tire, one direction for front tire mounting and one for rear mounting.

Above is correct. I had to swear today as I just spent about 20 minutes wrestling a schwalbe marathon winter onto my new wheel, only to then look and realise the direction was wrong!!

It points to the rotation of the tire as you move forward, regardless of where you are looking at the arrow.

If you were just riding on paved roads you would not need any patterned tread... the irregularities in pavement provide a rough enough surface to provide all the traction you need as the tyre will conform to these as you roll along.

With many directional tyres (treaded) they are designed to roll faster when mounted in one direction and offer a little more traction when they are mounted in reverse... some tyres are also front and rear specific to further maximize performance.

In the winter I reverse my rear tire's tread for snow riding. Honestly, I think it's because I like the sound more... Extra traction is nice, too.

OP, your picture shows things correctly as far as the arrow pointing in the correcting intended direction of tread rotation.

Along the lines of SF's post, I usually think about traction when mounting my *mountain bike* tires. I'm most concerned about the front tire for braking and the rear for acceleration, so I mount the tires in the orientations with most traction for braking up front and most traction for acceleration in back; these are normally opposite orientations.
Here's what Sheldon had to say: http://www.sheldonbrown.com/tires.html#direction

The V tread is to prevent aqua planing. When the tire rolls onto water, the water is squeezed forward and to the sides by the V pattern. Since you have to be going 200 mph on narrow bike tires to aquaplane with smooth tires, the direction you mount the tires has no practical effect. However I always mount my tires with the V pattern pointing to the front on the top.

I thought it was 176mph? I guess it depends upon the pressure and tyre-width.

I'll bet there is a "direction of rotation" indicator somewhere on the sidewall. It can be hard to spot.