Businesses would suffer, but hospitals might be okay (for a little while)
User table_rock claims to work for a manufacturing company, saying that his business would be completely shut down during a two day blackout: "We couldn't purchase supplies, manage inventory, receive orders, fulfill the orders we already have, process payments or invoices, or even ship anything." With several other users (who have unique, professional situations) echoing this sentiment, and agreeing the shockwaves would certainly effect their overall operations for months, even years.
As far as the ever-important hospital situation, Jabberminor, a hospital employee, says "...while the hospital has its own database, it still has to extract a lot of information from outside the hospital. Either its to do with patient information, or simply just from people going on the Internet to look up stuff." So the hospital could function, just not at full capacity, because most have temporary contingency plans in place already.