You may not know it, but there are a number of different options for motorcycle helmets. These range from the old thick leather helmets that were often worn by more traditional cyclists (think riders of Harleys and Choppers) to composite helmets with an open face to the sleek motorcycle helmets that are aerodynamically designed and have eye shields. The type of helmet that you are interested in will probably depend on the kind of motorcycle you ride as well as the specific style of riding that you enjoy doing, and all are easily customizable with motorcycle stickers and even patches on the old leather helmets.
For example, if you are someone who likes large cross country motorcycles, then you probably want to make sure that you have a strong helmet, but you do not need to have one that is aerodynamic as you are not going for speed. This would mean your best bet would be the composite helmet with the open face. You might want one with an eye shield, but because you will be going long distances while wearing your helmet, you want the comfort of not having to worry about the mouth piece. This can become hot and bothersome if you are on the road for extended periods of time.
If you are riding in a race or if you are on a dirt bike trail, then you will most likely want an aerodynamic helmet with a complete face and eye shield. This way you can make sure that you have the best protection available while not slowing you down. However, if you are riding on a large chopper style bike for leisure, then you might enjoy one of the hard leather helmets. No matter which one you choose, make sure that they provide the fit and safety you need.