Wow. Great topic. I love the discussion here.
Quantum computing has the potential to break all currently implemented forms of encryption, not just those used in bitcoin.
If and when this actually happens, every computer system on earth will be vulnerable. So you can bet that researchers, corporations and governments are working on better encryption methods as a contingency.
To contribute to the question asked by @cloudspyder, Will Quantum computing affect crypto? probably not because at its core, crypto is just a network of computers maintained by people and given enough incentive (such as protecting their wealth), people can adapt to any situation.