I'd always run my commuter bike as a SS/FG (flip-flop hub), because a derailleurless drivetrain is easier to keep clean and properly adjusted.

However, when child #2 was born in January, I knew I'd want to be able to tow a 2-seat trailer uphill without punishing my knees. So now I run a Sturmey-Archer 3-speed IGH. The middle gear preserves the original ratio, and that's where I keep it almost all the time.