This. Seriously, OP. Consider a used Prius. They have very high satisfaction rates out of any vehicle. Also, they have great fuel economy and emissions. Perfect for city driving too.
If I was going to shell out up to $15k for a car, needed something with good gas mileage, and was doing significant city driving: Prius the whole way. But, I wouldn't buy from a dealer. :/
I'd stay away from the diesels. They have worse smog emissions.