Next time you have to select every other edge, face or vertex, you can select one, then the other however spaces apart you want your selection to be. Then hold Shift Ctrl and press the "+" key on the numpad. This will continue selecting in a loop exactly like you wanted.
Nice one, didn't know that one either.
Be aware though that it only selects the next active one, so in order to get this working with Edges you must be in Edge Select Mode.
This also means that it doesn't work with Edge Loops or so. Also. when there are many Edges (or Faces/ Verts) to be selected, Checker Deselect is way faster.
Awesome tip, thank you! I did select all, checker deselect, and box-deselect the outer edges to achieve this quickly, but your method is even faster and more efficient.
