If you don't need a front suspension, and you're mainly on the road, I'd get a cyclecross bike. I've got a Fuji Cross that I switch tires out on, depending on the ride. It's got 700x25c slicks on it most of the time, but it will take up to a 44c knobby tire.
Mine's a dropbar, but they make flatbar cross bikes, too. They really are the do it all bikes, since they handle paved roads, gravel, dirt, and light singletrack.