My car got 33 MPG on my trip to and back from Alabama this weekend. I was by myself and not carrying a heavy load or anything, but I still think that's pretty remarkable.
I know part of the reason for the great mileage is the fact that I put ethanol-free 93 octane gas in it. This makes a noticeable difference just driving around home, getting me 20 MPG instead of 17 MPG that I get with 10% ethanol 87 octane. But 33 MPG on the highway is a huge jump that I did not expect.
I also kept it at 65 MPH on the interstates, which helped I'm sure. I like that speed not only for the better fuel mileage but because it's just more relaxed since you don't have to worry about passing nearly as much.
I know there's debates about how much advantage you get by putting the ethanol free and/or premium gas in these engines, but I can attest at least in my own experience that it makes a significant difference. Yes, the price per gallon is going to be more, but I've done the math and in my area getting 20 MPG instead of 17 MPG makes up for the price difference. The cost per mile ends up being about the same.