So Obamacare is upheld as a 'tax'. The government can order people to purchase any good/service of its choosing as part of their 'tax' power. My opinion of this possibility was perhaps best elucidated here.
What can't the government order people to do as part of its 'tax' power? The answer, clearly, is nothing. Absolutely nothing. 
Little did we know, the 16th Amendment was a stealth repeal of the U.S. Constitution.
Gateway Pundit says:

FLASHBACK: Barack Obama Promises to Cut Taxes – Now Owns the Largest Tax in US History
From Neo Neocon:

“Ah, but it’s not a mandate, it’s a tax,” says SCOTUS
Justice Roberts has joined the liberal wing of the Supreme Court in ruling that the HCR bill is constitutional, 5-4.
It seems that, when faced with the dilemma of possibly invalidating a huge act of Congress, the Court sidestepped that particular steaming pile of doo-doo and accepted the Democrats’ position that, although they were careful to make sure it was not called a tax for the purpose of passing it (a political move), it nevertheless could be considered a tax for the purpose of constitutionality (a legal one).
Reports are preliminary; more, much more, will be coming later in the day. But it also appears that the individual mandate was votedunconstitutional, 5-4. That doesn’t matter for the purposes of Obamacare, which stands. But it matters for considering the all-important issue I mentioned yesterday in this post:
"I’m far more concerned with the precedent the Court will set regarding the further expansion of the Commerce Clause [than with its ruling on Obamacare itself]. If the Court fails to declare a federal mandate of this type unconstitutional, that would be an enormous triumph for “progressives”—far beyond the momentary victory of the Court’s upholding Obamacare."
From Rush Limbaugh:

The Court Rules: Obamacare is the Largest Tax Increase in the History of the World

Obamacare is nothing more than the largest tax increase in the history of the world.  And the people who were characterizing it as such were right and were telling the truth.  We have the biggest tax increase in the history of the world right in the middle of one of this country's worst recessions.