Just because you're doing 5 over doesn't mean you belong in the fast lane.
SLOWER traffic! Speeding or not! I can't tell you how many times I have to flash someone to get their attention that I want to pass them.
I drive about 800 miles every weekend and you'd be surprised how many people park in the fast lane doing 72 miles per hour. Seriously? *grumble*
I usually set the cruise on 80-85.