Originally Posted by
Bacciagalupe
There's no "best."
Cantis or v-brakes both work fine, parts should be available fairly widely. Both work fine in the wet. Cantis are a little more adaptable to a wider range of road levers without hacks like travel agents.
Discs work well, as long as you have proper braking technique. Parts may be a little harder to come by, so if you're doing a really long tour you'll likely benefit from carrying spare brake pads. They're not in wide use for touring bikes yet, so going disc will narrow your options a little bit.
I'd go further and say that
all high quality brakes work well (there are some exceptions but, thankfully, they aren't made anymore) as long as you have proper braking technique. I'd even go further and say that poor braking performance is (usually) the fault of the operator and not the brake. Knowing how to use the brakes is far more important than what kind of brakes they are.