I have the Avid Single Digit 7 brakes paired with the Speed Dial 7 levers. I replaced a stock set of Tektros with them and WOW, the difference is not even describable. Way less finger pressure needed and the stopping power is almost dangerous until you get used to it!

You can see pics of them on my bike by checking out my page here and you can get a good deal from Pricepoint for $89 out the door here.

Good luck with your selection.