Just been reading "running with the Kenyans". One of many factors that the author ascribes their success to is that when the Kenyans rest (which they take very seriously) they really rest, that is they do nothing. They sit around, watch tv, sleep.
Easy runs are pointless, either train or recover, not some wishy washy inbetween activity that you're only doing because you feel guilty about not doing anything. Rest is absolutely vital, it's when your body has chance to repair and adapt, if you don't rest you won't get better.