Unless money or space is a limitation, I'd have two bikes. Weekend speedy bike, weekday commute bike.
The commute bike wears wide tires, fenders, lights, bell, lock, maybe rack; it is heavy, kind of sluggish, dirty; you ride it as fast as you can, but boy it takes a lot of effort.
Then on Saturday you get on your speedy bike; it is light, fast, shiny; you feel like the wind. Give some thanks to the legs you built, in part, by pushing that heavy commuter all week.
I've never rented a bike here. Try Waterfront Bicycles, they are right downtown and have a pretty big rental fleet, all kinds of bikes.