I just got a new Prius - best gas mileage out there PLUS the trunk is large enough to fit things like Ikea furniture....so it's green and practical...and I love it, it's nice inside too. They were having really good deals on financing when I got it last month....best purchase I've made in a while.
It's a little pricier than some of the other suggestions but it holds its value and I've had it 6 weeks and only filled the tank up twice.