There are many different types of wood flooring, some common others you've probably never heard of. Each type of wood has its own unique characteristics and will respond differently to its environment over time. You need to know what your choice of wood will look like in the long term, some changes might be a lot different than you expect and will not go with your style and decor.
You need to educate yourself about each species of wood and its particular characteristics before you begin shopping for it. Some wood types are not as durable as others, so to be sure you are going to be happy with your floors in the long run you need to have realistic expectations to begin with.
There will be variations in your wood flooring. No type of wood is completely uniform unless it is manufactured that way. The more natural the wood type you choose, the more variations you will see once you floor is installed. Choosing an exotic wood flooring type is becoming more and more popular because of the statement it makes about a person's taste and style. The most common types of exotics are: Brazilian Cherry, Brazilian Walnut, and Santos Mahogany. Visit http://www.drakeshomeimprovement.com for a complete list.
These are generally imported from South America, Australia, the far East and Africa. Using these wood types for flooring requires that you be well informed as to the wood's appearance, stability, and hardness and how they react when used in the HVAC systems found in most homes. Be sure the type of exotic wood flooring you choose will work with your home's environment before ordering and be sure to buy from a reputable importer to avoid be ripped off.
You should always choose your wood style by looking at real samples. Viewing color and grain in photos or online is not reliable enough for you to judge.