With an optical mouse that fits the hand comfortably the wooden
tabletop works just as well as a hairy thigh. Actually, I'm surprised
ball mice are still around in the stores.
I have a preference for optical mice too, but ball mice do have their
place. Some gamers prefer them, and I can see why, first, ball mice
don't react when you lift them, so you can more quickly lift and glide
without your character spazzing out. Most opticals will react to
being lifted and moved, unless you lift them in a wide arc (ie. high
off the pad before setting it back down). Some gamers don't like
having to do that.
That said, I really do think ball mice are an endangered species. The
only ones I've seen recently were "surplus" being sold at considerable
markdown, or from oddball manufacturers, and many stores don't even
stock them anymore.