ARRRGHHH - marking pens!!! I must have a dozen - disappearing ink ones (great except that you can't mark ahead of time - the ink disappears!!!), soapstone (doesn't work), soap slivers (are you KIDDING????), pouncing (forget THAT - BIG mess), pencil style - they work for a little while, then you sharpen them and the points keep breaking off..
My mom gave me one of those chalk marker sets with the different colored chalk sticks that you slide into a holder. Those are pretty good but they do tend to break easily as well.