If you are looking to work up to long rides where speed is a secondary consideration to comfort, don't rule out touring bikes. You don't have to do loaded multi-day touring to enjoy some of the features of a good touring bike. They are very similar to road bikes but with more relaxed frame geometry and longer stays which makes trades a bit of agility for stability. They also have the advantage of being able to be fitted with racks, fenders and other accessories, and to take larger tires than most road bikes. If you are looking at hybrids and road bikes, but leaning toward the road bike, a touring bike might be a good choice.

A cyclocross bike is also similar to a road bike with a more aggressive geometry than a touring bike, but they will still take wider tires and fenders. They are an excellent choice for an all-rounder and are well suited to those who want a bike that will handle gravel/dirt trails and paved surfaces equally well. With the right tires and gearing, they are quite at home off road, similar to what the old rigid framed MTBs were designed for.