I use Avid Shorty 6 cantilever brakes. With the original pads, for some reason the rear brake was more powerful than the front. I switched to dual-compound Kool Stops, putting in only the front pads first. It had a little bit more power, but the rear was still outperforming the front. I put the second set of pads on the rear and switched to a much shorter link wire on the front brake, and the power increased significantly. They give me good enough performance that I am comfortable making quick stops and riding down hills with the bike loaded full of groceries, though I know they could still be a little better, so I may move up to long arm cantis. Though the Kool Stops didn't blow away the stock Avid pads for dry braking power, they have a better feel when braking hard, don't make any noise (the Avids would scream if they got wet), stop way better in the rain, and don't get black gunk all over my rims.
Here's the rear brake with the original link wire. Notice how high the yoke is above the fender compared to the following picture:
And here's the front brake with the shorter link wire. It went from a 106mm wire to a 73mm wire and the braking got way better:
And look how shiny and pretty my braking surfaces are:
