Sram G2 RSC Disc Brake
In our opinion the perfect trail brake is lightweight, powerful, and easy to setup. The G2 is just that. The RSC version has a pad contact dial which allows you to get your perfect feel on the lever so the brakes are there for exactly when you need them.
Sram also uses levers that can be used on either the left or right side of the bars - just cut the line to size and you are good to go!