What form factor are you talking about? If you want an econobox, get a Honda Fit. Lowest total cost of ownership of any car you can buy right now, but get it with a stick. Too underpowered to have adequate performance with an automatic.
If you want something with a little more room, a Mazda 3 hatchback. We have one, gets around 29 MPG overall, and very peppy in spite of it – of course, it’s a stick, too.
If you want a sedan, consider a Ford Fusion Hybrid. It’s got good power and good mileage to boot, but it’s not cheap to buy.