Suppose I'll be helpful. Not because I want to, but because I can't think of anything clever.

Thinking in gear inches would be more helpful than thinking about a gear ratio to start off with. For commuting on flat city streets I would suggest any gear ratio that will give you 60 - 75 gear inches depending on if you are riding fixed or single speed and your fitness level.

Use this website and some trial and error to find out what you prefer: BikeCalc.com - Fixed Gear Calculator

It would also help us to know anything about current bikes you ride.

#KiloTT

Edit: Wanted to post this too.