No Obama didn't really buy it however a lawyer friend of his in Chicago did for $8.7 million. I would have been really dispointed if he had. I think it would have ruined the whole show for me. See link below. Obama not buying 'Magnum PI' house: White House
I think it'd be cool to have the estate go to someone famous. Obama's from my generation, so probably knows/appreciates it.
Someone famous would be cool but not Obama or any other ex-President. The security that would be around an ex-President's house would ruin it for anyone that wanted to go by an take a look. No more wading in the tide pool or peering into the gates then.