Townie bikes fall into the categories of "comfort" or "cruiser" bikes. These types of bikes are usually heavier than other types, but they're built for comfort, not speed. Cruiser bikes feature plush saddles, relaxed geometries, lever brakes, step-through frames, and come equipped with front baskets or rear racks for carrying cargo. A Townie is good for a casual stroll through the park or on the beach, but because they are heavy and slow, they may not be the best choice for riding distance.
"Distance" is a subjective concept when it comes to cycling. For professional distance cyclists, a ride under 50 miles may be considered short. For a beachgoer just looking to cruise the strip, a few miles could seem like a significant distance. To keep it simple, don't expect to keep up with the speed or distance of someone on a road bike while you're cruising along on a Townie. However, if you think that the 5-mile round trip to the grocery store and back is significant, or would like a bike to cruise a few miles down the beach, a comfort bike may be perfect.
If comfort is your primary concern, you'll be hard-pressed to find a bike more comfortable than a cruiser -- for short distances, at least. These bikes often have big, soft tires and front suspension to absorb any bumps or cracks you may roll over. But because they're big and heavy, cruiser bikes can wear your legs out quickly and make distance rides very tiring. Also, the creature comforts that are standard features in Townie bikes, like wide, spring-loaded plush saddles, are only comfortable for a short duration.
If you're interested in using your bike for moderate to intense cardiovascular exercise or plan to go on rides that are at least 20 miles in length, a hybrid or road bike would better serve you. If you're not aspiring to ride with groups at top speeds, but would like to be able to get a good workout, a hybrid can provide a nice mix of comfort with a dash of speed. However, if you'd like a bike that you can take out at high speeds for 40 to 50 miles at a time, a road bike may be more your style.
Importance of Fit
Regardless of what style of bike you end up choosing, make sure you try it out at a bike shop before purchasing. If possible, have a bike professional guide you in choosing the right size and properly adjust the bike to fit you. Be aware that cruiser bikes have fewer adjustment points than hybrids and road bikes, but if you're new to biking, it's still a good idea to have an experienced cyclist help you get set up.