Choosing a Trademark

From Patent Pending:

"When selecting a name for a company or a product, you should think about what type of mark you have selected. Not all trademarks are capable of being registered, nor enforced as trademarks. The Patent and Trademark office divides trademarks into 5 categories: generic, descriptive, suggestive, arbitrary, and fanciful. Each category is treated differently. "

The categories in increasing order of protectibility are:
Generic, Descriptive, Suggestive, Arbitrary and Fanciful.