I am a free-market libertarian. I believe the federal government should stay out of anything that the Constitution doesn't explicitly give them the power to do.
HOWEVER, healthcare just doesn't work in the free market system. If I want an apple, I can shop around and buy the apple that gives me the best value. If I'm lying in a bed about to die if I don't have surgery, I really don't have the option. I would pay any price. Therefore, the only real solution to healthcare is a system like the UK has, where the costs are paid through taxes and everyone gets "free" care.
Since that will never happen in the US, I think the only real solution here is to detach health insurance from employment and to allow interstate competition from insurance providers. A larger pool of people and increased competition will lower costs. Don't mandate coverage, but do keep health insurance premiums as untaxed. In essence, make it much closer to automobile insurance. If I choose to not get coverage and get in a big accident, then I'm stuck paying out of pocket. Make it the same with healthcare.