Which iPod should I get?

Well, last year, my iPod got stolen. So now I am looking to get a new one. I am a very indecisive person, so I need help. I want one of three. The 8GB Third Gen Nano, this is the one I had before. The 16GB Fourth Gen Nano, this one doesn't look that good to me, but it doesn't look like it is prone to theft. The 8GB Second Gen Touch, this one looks really cool, but it looks large, and in turn, prone to theft. Also I am really scared of theft and do not want a repeat, but I am not that kind of person to like check my pocket 24/7. So yeah.