Sandy is a large, disorganized storm, buffeted by bad luck (high tides) as it smashes into a dip of arctic air in the gulf stream. It is a hybrid storm, and it is a rare occurrence, but really... I don't believe the resultant damage will be any more severe than usual.
I also believe that if it does plow into the Appalachians as forecast, that the storm will rapidly degrade.
Sure, there will be squalls, wind, and rain - and there will be power outages and blocked roads, but nothing more than the same sort of results any large Nor'easter is capable of delivering.