I use flatpedals with toe clips and straps, on both my fixed gear and singlespeed. I like them they work well, and I can wear any type of shoes I want. Riding in hilly terrain on a SS will make you into a mountain goat , you'll be in great shape after a while. As for gear ratio you'll need to experiment untill you find something that works for your style of riding and terrain. Try 42/18 and see how that goes, also remember that spinning is healthier then mashing.