I'm going to keep promoting this until the 20th and I see some serious shoes flying.
If you're uncertain as to which shoe to throw, might I suggest a few tips:
1) Pick a shoe you have zero interest in. After all, you may not get it back after you throw it. Have no regrets when you throw it so choose one with which you have minimal emotional attachment.
2) Select a shoe that makes a statement. A stiletto, perhaps, sends a fine message to the world that not only are you crazy enough to wear those things, but you are of a generous heart - willing to forgo your style in the name of dissent. That sharp heel also communicates that you are serious about your throw. The aerodynamics of a stiletto can be lethal.
3) Throw the most grotesque and foul smelling shoe you own. 'Nuff said.
4) Throw a sneaker with a sock stuffed in it. The extra weight might carry the shoe further in flight, thus resulting in much higher likelihood of hitting target.
5) If you're still not sure if you're down with this shoe throwing event, well, I suggest go light. Choose your bunny slippers or whatever you schlep around in when in the privacy of your home. Their light, compact, and even if it hits the target, feels more like a brush of cotton in the face than the regular weight of a snow boot.
Prepare for the throw on 1/20/2009. Spread the word.