It might be a Cat 2 now...
It's not cat anything, because it's not technically a hurricane any more. The way insurance claims are set up, the deductible is vastly different between noreaster & hurricane ($500 vs 10% of the property value (or more.)) The NHC is expected to go by the scientific definitions & be impartial. Impartially, it's not a hurricane. But, if you want to call it a cat 2 due to winds, that's probably okay; it's currently strengthening (see my post about a day ago - this was expected before landfall, with it rapidly diminishing in strength at landfall.) In terms of pressure, it's a cat 4.
In terms of Integrated Kinetic Energy, Sandy is probably the most powerful storm in history to hit the US. IKE has been considered as a replacement to the Saffir-Simpson scale as it more accurately predicts damage.