I read an article in the Economist not to long ago, that seemed particularly insightful. It's about investing, but I think it applies equally well here.

http://www.economist.com/news/finance-and-economics/21569397...

Here's the money quote:

Investors selecting a sector on the basis of its prior five-year performance would have earned much higher returns over the following five years by selecting the worst-performing sector than the best.

So if you're looking for an idea of what business to launch look at what did the worst over the last five years... Rather than what did the best (obviously this is just one thing to consider out of many, but I think there's a lot to be said for it.)