What is a good, safe, roomy sedan that gets good mileage?

We have a baby on the way, and I want to buy my first car. I'd like to get a car that is environmentally friendly, or at least gets good mileage. And safety is of course a big issue. Is there a roomy, safe car that also gets good mileage? No SUVs, no minivans, and preferably no station wagons please.