Not really new information, but I agree with all of the above posts. Properly adjusted cantilever brakes with new and decent pads can and should stop you just as effectively as v-brakes. If you do go with v-brakes, new levers will be required due to the difference in mechnical advantage. Look up Sheldon Brown's article online about this if you want to know specifically why - but the short version is that your current levers are not compatible for safe stopping on v-brakes.
There are a few options (Tektro makes a popular set, as mentioned) but most drop bar levers are made to work with cantilever or traditional center/side pull brakes - you'll pay a premium for mixing things... I would be suspicious of a shop that tells you to replace the entire braking system instead of just re-greasing the moving parts and putting on new pads and cables.