Once gas prices topped $3/gallon here, I started setting my cruise control at 65mph on I-94(70 limit) and adding Lucas UCL to every tank of gas.
I still cruise at that speed and use the Lucas, and I just set a personal record of 29.4mpg, mostly highway. EPA sticker says 19/25mpg, so I'm pretty happy about that.
People pass me, but who cares. Not me. I enjoy the commute and listening to music. Plus, increasing my speed to 75mph(like most people drive) would only shave 3min. off the trip, not worth the 5mpg drop it causes.