I aplaude your efforts to improve your kicking abilities. All the exercises mentioned here will definately help, however, you should also focus on timing your kicks as well.
Why timing? A brief biology lesson. Your muscles are made up of three types of muscle fiber - white, grey, and red. White is the fast-twitch muscle fiber, and red is the slow twitch. White is commonly associated with exsplosive movements and red is associated with endurance and power. Grey, as I understand it, is sort of an adaptive fiber to the type of activity you do. If you run long distance, those grey fibers will change to become more like their red cousins. However, if I remember correctly, they don't convert to white fibers even if you do train for explosive movements. The point I am trying to make is that your body is composed of a limited amount of white muscle fiber and no matter how much you train, your will only get to be so much faster if your genetic composition lacks sufficient white muscle fiber. Also, when you get older, you may not have those muscles to count on any more, particularly if you take on a sedentary lifestyle. But if you have timing and distance skills down pat, your kicks will look lightning fast and they will have plenty of power. Best of luck to you.