This really depends in what country your in and your investment time period.
Generally speaking clean energy stocks would make a good long term investment, but I would do a lot of research and be very selective.
In India I hear telecommunications is a good sector to start.
At the moment I don;t like anything in US dollars although I like Google at the moment even at its current price.
In Australia solar energy and resource stocks and engineering company's supporting mining companies are well worth a look as well as our banks which are basically the exact opposite of the US banks, my top pick is ANZ.
In China I would look at car makers (electric), and shipping.