Your favorite rear end/final drive ratio and why?

Highest possible gear the rear chunk will allow. I have a 2.76 open in the 8-3/4 in my Challenger and a 2.50 in the 9" of my Fairlane. I'm 45 highway minutes from anywhere and like being able to hold the fast lane (75~80mph)without sounding like a NASCAR event at 4k rpm.