I just read a very interesting point in the book Ready for FCE. The question was about the difference between I lived here for two years, and I had been living here for two years. Apparently, when you say the first, it means you don't live here anymore, and when you say the second one, you might be living here or you might not.
I wonder if it's rigorous grammar and in everyday English, speakers use the first statement even if they now live in the same place where they used to.