How did you decide where to live? (Montpellier)

My wife and I spent 5 lovely days in Montpellier last October as we have started our research on where in the world we want to retire to (less than 9 years), and were very pleased with all this city has to offer. My question is, how or what aided in your decision in where to put down your roots?
We will be looking at a couple of other areas (like Toulon and even Vence), our requirements are near an airport, with a train station and local transportaion - like the tram system. We've been to Paris and Nice but the costs are beyond our limits so does anyone have any other suggestions?
Our goal is to come back for a longer look and see if our search is over or if we need other choices. Thanks for your help.
John & Robyn