I have a road bike, an MTB bike, and a CX bike. The CX is, by far, the most versatile of the 3. There's a big network of dirt (and some gravel) trails behind my work that are perfect for the CX bike. When I want to ride it on the road, I swap in another set of wheels with road tires on it and it works great on the road. I've also put more aggressive treaded tires on it for trail riding.

Bob