Cantis look interesting and there's a certain vintage nostalgia about them, so I don't want to knock them. I almost went with them on my CX setup, but thought better.
Cantis are difficult to setup and keep adjusted correctly, yes I know, I suck as a bike mechanic. It's easier to just give up on them, but if you have a nice pair on an old bike then maybe stick with them.
There is NO reason, however, to go out and buy a cantilever brake. The parallel push of a Shimano XT or XTR simply destroys Cantis in feel and power. This is also the easiest brake to set up on the face of the planet, never goes out of adjustment and starts rubbing randomly like sidepulls and cantis do. This was the most annoying thing about cantis and side pulls. You nudge them slightly pulling them out of the car or at the bike rack and they're off rubbing. Maybe you guys would like to debate that such and such properly setup Canti works well or has good stopping power, but all in all good V brakes are better.

Oh, and for drop bars, Tekro 520 levers are $20 on ebay and give a nice linear pull. I'll be welding studs on the rear soon so I can get ride of that annoying side pull.