What is the IT Hot Spot today?

I have chosen early retirment from a Fortune 500 Computer company to persue new direction.What technology, proces etc is currently “in demand” or today’s IT hotspot? Linux? Lindows? Supply Chain/B2B? Applicatiion serves,Internet Security etc.
Internet security would seem a viable way to the pay bills for years to come.
What is the hottest and people demanding area of IT today for both employer and employee?