The easy way is just to use wire staples on the back, but that seems a shame if you're going to make the stands.
A clean, fairly easy way is to drop the wire through the stand.
Drill a hole in the top and bottom plates of the stand, and route a small channel to run the wire from the hole to the back of the stand. Make sure you drill the hole big enough so you can tie a small weight to the wire. That will make it easier to fish it out at the bottom.
If you really want to get fancy, build in the wire terminals as part of the stands, and leave the wire inside permanently.
Are your wires coming through the floor, the wall, or just along the baseboards?
Disclaimer: I actually have all my surround sound wires in the walls. Upstairs we have surround speakers on the walls. I ran the wires before the drywall went up. In the basement I just finished, the wires are in the wall, and we have all in wall speakers.