Some days ago I eard on a TV show about cars that a hybrid car has a larger environmental cost than many other cars!! I found it really surprising so I tryied to look for some information about this topic. Well… hybrid cars may spend less fuel but that’s just a little part of the story. The environmental cost is not just the carbon dioxide sent to the atmosphere.
Take a look at the links below to have an idea of the whole picture.
http://clubs.ccsu.edu/recorder/editorial/editorial_item.asp?NewsID=188
http://digg.com/tech_news/All_you_need_to_know_about_hybrid_cars
The punch line of the story seems to be: if you want to be environmentally friendly when driving, buy a nice new small city car like citroen C2 or a Renault Clio or some car with similar characteristics. 
jmgs
pgomes
filipefernandes