Interesting thread. I'm currently considering a Super Duty for my next truck, although it won't be new. I'm currently tracking the fuel economy of my current ride, so I have a baseline as to what's acceptable or not :-p
If I can get more than 20% better mileage out of the 6.0 Powerstroke, I'm definitely thinking of going that way (diesel is typically a 10-15% premium here). Changing those two-piece plugs on the 5.4 every 60K doesn't exactly sound like a lot of fun, and gas F-250s seem harder to find.
