Level Vertices

If you find yourself in a situation similar to this, there is a quick way to level the vertices.  The approach is to scale to 0, along the axis that is perpendicular to the plane of alignment.  So in this case, I want to scale the two vertices to be level along the z-axis.

The command sequence to do this is to select the two vertices, scale [s], the lock to the z-axis [z], then type [0] to zero the scale.  This will align the to verts to the center/pivot point of the two.