I would say Walk through the Fire, because apparently it actually was one (or at least in Germany) Also, out of all the OMWF songs, it's the one I've got stuck in my head most often. The next single would be Under your Spell, because popsingers tend to release an uptempo song as their first single, and then a more romantic/ballad like song. But yeah, I think WttF would be Buffy Band's I kissed a boy, or Mercy, or Smile, I guess.