Depends on who you talk to imagex. In all honesty, "cure for cancer" is pretty misleading. Let me explain. I study trace metal chemistry in contaminated soils, waters, and sediments. Through understanding the reactions that take place in the environment, we learn how to (a) better evaluate where the true risks to humans and ecosystem are and (b) manipulate reactions to better remediate contamination. Many of these metals are carcinogens (cause cancer). Would it be fair to say I am working on a cure for cancer then? Nah not at all.
What the distributedfolding and folding@home projects are doing that is important is open source science in my opinion. There's no possible way that problems like "can we mathematically model how proteins fold to eventually predict what proteins SHOULD look like?" can be done by a single computer or supercomputer even. Sure one day waaay down the road it may correctly optimize a protein useful in cancer research, but it's providing a wealth of good results on HOW scientists and overclockers and IT people and average joes can come together and benefit from technology and the internet. The world is becoming a renderfarm in some ways.
As this research gets closer to actual product development, I would suggest that we find out what pharmaceutical companies are involved and who will profit from the drugs produced. They should be paying for our electricity and water cooling since they'll make billions off our efforts
