Shimano Nexus 3 Speed
The Shimano Nexus 3 speed gears have really good extremes, and are perfect for any city bike. Here is how I find the nexus range -
The best part about the Nexus gears is that you can change gear while stationary. Imagine pulling up to some traffic lights in a hard gear, on a normal bike you would have to wait until you have pulled away to change down to an accelerating gear. On a nexus, just stop, click down into first and you are ready to pull away when the lights change.
Also super handy when you are starting on a hill.
I have scaled up Albion hill (Brighton) in 1st and can cruise nicely at 15mph in 3rd. The gears are quiet, efficient and reliable. Matched with a rust proof chain, this is a true fit-and-forget setup.