In my younger years, I was a left-laner going as fast as I could get away with. But now we try not to exceed 65 (usually we drive at 60 max). It's surprising how many people are hanging out in the right lane going our speed. I tend to watch the rear view mirror more than what's in front to make sure I'm not holding up traffic, and it's so much more relaxing. In our setup, there's a large hit on gas mileage going fast. The air drag at 80 mpg vs 60 mph is (80 / 60) squared, or 78% more drag.