I was surprised and happy that I got over 60k miles out of the OEM Goodyear tires, but tire time came and I wanted some black wheels, so I went up to 17" wheels and put on some 205/55R16 Continental PureContact LS tires.
I'm not sure which piece of this setup is the biggest culprit, but my fuel economy dropped dramatically. In the middle leg of my commute where I used to routinely top 70 MPG on my last 25-mile average and where I've hit 80 MPG a few times, I struggle to top 60 MPG now. Hand-calculated tank averages are running 50-52 MPG, which, while still pretty respectable, is a big shift from the easy 55+ MPG I used to get. I doubt I'll see a 60 MPG tank with these wheels and tires.
The PureContact LS is listed an "Eco Foucs" tire and I have them aired up well above what's specified on the door sill. I guess there's something in the tread or tread compound or just that little bit of extra width that makes all the difference. It feels kind of like it did with the Goodyears when I was driving in the rain, which always ate into fuel economy a little.
Now, it handles great. The tires are slightly wider and the sidewall is stiffer and understeer isn't a thing any more. And it looks pretty sharp with the new wheels. But I really miss going 700 miles before the fuel light came on. I'm fueling up between 600 and 650 miles now.
So... choose carefully if you want to keep your fuel economy.