A recent web based calculator from our friends at Project Get Ready (led by the Rocky Mountain Institute) will calculate the cost to own a variety of vehicles for you and compare it to similar vehicles. The initiative aims to prepare cities for the deployment of plug in and full electric vehicles. A very cool function is the ability to insert your own driving assumptions, fuel prices and other important factors. EU residents will need to convert to Km and liters, and account for different tax incentives, sorry.
There are 48 models to choose from including hybrids, full electrics (including the not yet released Tesla Model S), and a few ICE cars. If you really want to make a point with your skeptical friends, you may need to look up yourself the full cost of owning the lesser efficient models not on the comparison list. This is one of the best, free sites around to perform your own analysis. More importantly, you can now produce a graph to demonstrate to your friends, with your own assumptions, when and how your hybrid/plug in will pay for itself.