I have recently noticed a strange noise coming from what seems to be the front driver's side when I brake. I sounds like a "click" and I can feel a slight thud inside the car. This doesn't happen all the time, but usually if slowing down from around 40+ mph, like around town driving. It seems to happen every few times I decelerate. As in, once I hear it, the next time I brake it is not there, but after that it returns. Any ideas guys?

ps:
Also, as i just redid the suspension I am starting to look up upgraded braking systems. Suggestions? I remember CHP liked the Stainless Steel Brake Company's tri-force front rotors and calipers...thoughts?