Cmk,
You don't state whether the floor joists overhead are exposed or not. If it is still an unfinished area, the solutions in the above post would certainly help. However, should you want the more "finished" look of drywall, there is a system of vibration isolating metal rails that mount crosswise to your joists. Drywall is then fastened to it. These rails are designed to isolate vibrations from being passed through from above. I would still use the sound batt insulation too. These measures should greatly help, but I doubt that the clicking of hard soled shoes on ceramic tile will be totally eliminated. There is also a special type of sound deadening drywall on the market which also would help.
Perhaps the least expensive solution is to only wear your slippers when he is down there! 
