The question is, will they strike down the whole law, or just the mandate? If they just strike down the mandate, the insurance companies are still bound by the ban on pre-existing conditions requirement, which will bankrupt them because then people can just wait until they are sick to get insurance.
The really clever play would be for Obama to veto any change to the rest of the law, with the Democrats sustaining the veto in Congress. This results in the implosion of the private health insurance industry, and we get single payer universal health insurance by default.
I love it when a plan comes together.