All motorcycles share some fundamental characteristics, but as their popularity and versatility has increased a surprisingly wide array of motorcycle sub-types have evolved to suit riders' needs. Some want to be able to take regular cross-county trips on the interstate superslab while still others prefer to jump off the highway to ride through dense woods on narrow mountain trails. If you're a new rider you might be feeling a little overwhelmed at the variety of motorcycles available. If so, don't worry--I'm here to help you make sense of it all! The list will go in order from most road-oriented to most dirt-oriented. Keep in mind that there are large and small displacement motorcycles in each of these categories. As a beginner, leaning towards the smaller displacement machines is wise.
Tourers: Touring bikes are the cruise liners of the motorcycle world; massive, comfortable, luxurious and hard to maneuver. Filled with gadgets and amenities to keep you comfortable for long hauls they feature lots of wind protection, excellent audio capability, comfortable seating, tons of storage, power outlets for things like GPS and more. They're designed specifically with long-distance riders in mind and in such a way that the rider is as comfortable as possible. Many tourers even offer cruise control as a standard feature! As a trade-off for all the extras you get on this type of motorcycle they tend to be very heavy, require large engines which use significantly more gasoline and are lacking in ground clearance. Don't expect to take one of these to the track--on even mildly spirited backroad runs you will be scraping your floorboards in the curves. They also take a lot of muscle to steer when riding at low speeds, in parking lots for instance.
Sport Tourers: These motorcycles offer most of the comfort of a pure touring bike but with an emphasis on performance. They tend to have significantly more powerful engines, sporty styling and ample ground clearance which allows for a much more aggressive riding style, though they retain much of the comfort and storage capacity so helpful for serious long-distance trips. Sport touring bikes tend to be nearly as large and heavy as their brothers, though they carry it more gracefully. Still not recommended for beginners.
Cruisers: Cruisers are all about style and hearkening back to the classic days of motorcycling. These roots show themselves as the preservation of old technologies (or lack thereof in the case of Harley's Hardtail series which has no rear suspension). They're meant to be flashy, imposing, and mean. As such they're generally heavy with chrome, often massive motors and thick steel frames. With such an emphasis on appearance a sacrifice of rideability has to be made, and this becomes apparent when you attempt to flog this type of bike on a windy stretch of pavement. Ground clearance is lacking and the rider will run out of lean angle quickly as they ramp up the speed. Good body position technique can help to offset this but ultimately you will still be limited by the bike's design. They can weigh as much as a gigantic touring bike with engines larger than a Honda Civic's. There are small, low-displacement cruisers as well though, such as the Honda Rebel which has a fuel-efficient 250cc engine.
Standards: Standard motorcycles have a comfortable upright searing position and good amounts of legroom. Taking long trips on these bikes is not difficult at all and can even be quite comfortable with the right seat. You might not have the luxuries of heated grips and a six-speaker mp3 player at your disposal as you could on a touring motorcycle, but riding all day on a standard is not difficult at all if you enjoy it as much as I do. Standards are typically quite modern in the way that they're engineered which makes them capable of very spirited riding. While they may not look as flashy as a sportbike modern standards come with plenty of great technology like fully adjustable suspensions, excellent brakes, and engines that make significant power for their size. All of these attributes contribute to the versatility and great handling of standard motorcycles. This class is the best place to start. Worth noting is that many standards are offered in a more sporty trim, with lower bars, higher footpegs, and full fairings if that's more your style.
Sportbikes: Built for one thing--speed--sportbikes are designed with the most aggressive riding possible in mind. This is the bike you want if you decide to get into trackdays or racing. Low handlebars and high footpegs allow for quick steering and enough ground clearance to get a knee down with ease. The engines are usually high-performance and high-revving with every possible ounce of power squeezed out of them. Maintenance is going to be much more difficult on the high performance engines seen in sportbikes with trickier valve adjustment procedures, lots of plasic fairings to remove, and often more frequent oil change intervals. Don't expect to go long distances on a thoroughbred sportbike too comfortably. The same low bars that allow for quicker steering and super-low body tucks can be hard on the wrists and back after a while as you have to use more of your strength to support your body weight. These motorcycles are highly strung and very sensitive to user input; steering, throttle, and brakes are all going to be less forgiving to a new rider. I wouldn't recommend a true sportbike to a beginner due to this much narrower margin of error. You're going to make mistakes as a new rider... Some bikes will give you a second chance. Some will punish you severely for them.
Dual-sport/Adventure: With their long-travel suspensions, slightly knobby tires and high stance these bikes are made to tackle unpaved roads with ease. Some favor dirt, some favor road, but all are capable of tackling some pretty rough trails. These are generally midsize motorcycles that I wouldn't exactly describe as lightweight, but they aren't hard to handle either. Just don't expect to take them on extremely narrow or winding trails designed for dirtbikes with ease. They will take some serious steering input on the harder trails, and due to their larger size are not quite as forgiving as a proper enduro or supermoto. You can go almost anywhere on these bikes though and they tend to appeal to people who like a good mix of paved and dirt riding over long distances.
Enduro/Supermoto: Essentially street-legal dirtbikes these are generally as narrow and light as possible with smaller engines, contributing to their excellent handling both on and off-road. They will take a lot of physical abuse and are designed so that they don't receive much damage from spills. Unlike the highly-strung sportbike, power delivery is more linear with lots of torque available from low RPMs. Wheels and tires can be swapped between street and dirt making them very capable of aggressive riding in both environments. Due to their smaller engines and shorter gearing for climbing steep hills they shouldn't be expected to win any top speed records. Single cylinder engines are most commonly used in this class which makes for a bit of a buzzy ride at highway speeds. Add to that fact that enduros have virtually no wind protection and a seat about as wide as a board and it becomes clear that it's probably not going to be the first choice for long-distance road riders. There's always a compromise!
Newcomers to motorcycling should avoid starting with a highly specialized bike of any kind until you're sure of what kind of riding you like to do the most. You might find yourself frustrated with your purchase of a big, heavy cruiser after riding a friend's dual sport on a forest road and realizing that you'd rather do most of your riding out in nature alone than with streetlights and traffic. Choosing a good all-around standard bike that can do a little bit of everything is a great place to start as you can try different types of riding to see what suits you best without getting into trouble. Try taking a 700 pound Harley on a windy dirt road to see what kind of trouble I mean. Regardless of what type of motorcycle you choose, hopefully this guide will help you decide which direction you want to go.