I'm trying to save some old redwood deck boards and all the screws are stripped out. I tried drilling the heads off, that didn't work. I wasn't about to "easy-out" them all. What I ended up doing is drilling holes large enough for the screw heads, just adjacent to the screw. It works.
Reclaimed boards will have holes in them but I'm not using them for anything fancy. I could just plug the holes too.
Here's a video of the quick-n-easy process: http://youtu.be/3t-8ZGddvq0