woah! Sincce u guys consider the sb600 at ~$350 to be cheap, I don't think I want to know the cost of the sb80dx! Anyway, my budget is abt $400-$500. I need to do basic fill-flash and standard flash where the flash is the light source on some occasion. Guess you could say power is a critical factor for me. Currently have the sigma EF 500st but from my old film camera days, after fitting it to the s3 pro, the TTL does not work. Using the Mn or Mx mode mostly resulted in incorrect exposure. My key concerns is that the flash has to be fully functional when fitted to the s3 pro and not only certain function, reasonably priced and as mention earlier, able to fill-flash and standard flash. Any other brand suggestions that have been tested and known to work with s3 pro are also welcome. Right now I'm still evaluating before deciding on which flash to go for.