Obamacare Decision Leads to More Questions

In reviewing the ObamaCare decision by the Supreme Court, I have several questions regarding the future of checks and balances on the power of the federal government and our economic freedom.

1. Have any limitations to the federal government's interstate commerce powers been set?
2. Does the federal government now have unlimited taxing authority?
3. If the federal government does not have unlimited taxing authority, what are its limits?
4. If the government cannot compel behavior via the commerce clause (as is mentioned in the Supreme Court's summary), can it compel people to conduct any type of economic transaction via its taxing powers?
5. What powers of choice does the individual really have if the government can regulate and/or tax every commerce transaction and via its tax power, compel people to participate in them?