I am really shocked by how many gas guzzling big vehicles so many people have. If you live in a city, I truly don't understand why you need a sport utility vehicle, especially since they have a fairly poor safety record and cause a lot more fatalities than regular vehicles.
I use the middle grade of gas for my car, which is a modest Suzuki Aerio. I love it -- it is sporty, zippy, great on gas, roomy for its size and best of all, runs like a dream.
If I had the money, I'd buy a Prius. There are a lot of Prius taxis here and they are fantastic rides.
Diesel is so incredibly polluting -- I can't even believe diesel cars are still legal in North America.