Which Plane Orientation Dissipates the Most Mechanical Energy?

[ViewtifulBeau]

The figure above shows three choices for the orientation of a plane that is not frictionless, and for the direction in which a block slides along the plane. The block begins with the same speed in all three choices, and slides until the kinetic frictional force has stopped it. For which choice is the amount of mechanical energy dissipated greatest?

The first figure is of a block on a horizontal plane.
The second figure is of a block on a sloped plane and the block's original velocity was down the slope.
The third figure is of a block on the same sloped plane, but the initial velocity was up the slope.

I thought the answer was the third figure, but it isn't. Now I think that all of the energy dissapated is equal because they all come to a stop. So all of the energy is gone. (but don't they stop at different times?) thanks

 

[FluxCapacitator]

Here's a hint, there's energy in many forms, kinetic, heat, and of course, gravitaitonal.