[AndrewJ]

nice, my old singlespeed was 46x16. So that puts you in the 75 gear inches neighborhood, that's plenty challenging for the climbs. There were only a few big hills that I couldn't climb (more like didn't want to climb) with my old bike, but it'll make you stronger in a hurry. You never really appreciate the "pull up on the pedal(s)" argument for clip-ins until you're grinding up a hill at 20rpm on a singlespeed or fixie. The ability to pull up makes all the difference.

That and making sure your handlebars and brake levers are (very) tight. You need them to be stable so's you can get every last bit of leverage out of them for climbing.