Chocolate has a long history, dating back as far as 1100 BCE. The peoples of the Americas (notably the Aztecs) used it in a drink (the original hot cocoa!), as well as in ceremonial activities. Wikipedia has a great page on chocolate.
Chocolate was initially brought to Europe by Cortes and those who followed him, having been introduced to it by Montezuma, with the first recorded shipment arriving in 1585 CE. The Europeans were not as enamored of the bitter taste, so added other items such as sugar to the chocolate.
As time went on, people, notably the Dutch, worked out the process of making what we today think of as Chocolate. Many variations on the theme exist now including varying degrees of "dark" chocolate (rated by cocoa content; more cocoa makes a more bitter chocolate), as well as "milk" chocolate (in which both sugar and milk have been added) which is much sweeter, and also "white" chocolate (which some insist is not actually chocolate at all!)
"White" chocolate is, strictly speaking, not actually chocolate. Chocolate, according to the various food governance organizations, must contain some cocoa solids, and white chocolate, or couverture, contains none. Differing standards organizations have different rules, and France insists (or did) on the term "couverture" (covering) rather than chocolate because of this.
White chocolate (note: I am not French, I call it white chocolate) is a fairly new arrival on the scene, dating from the 1930s when it was introduced by Nestle. Many people like it because it is sweet and has a little of the chocolate flavor, but no bitterness.
Taking chocolate from "bean-to-bar" has become a popular new business. Most of us don't really know where most of food comes from or how it is processed into what we eat. With chocolate, it is easy to understand why. The preparation of chocolate is very involved!
Chocolate comes from the seeds (or "beans") of the Theobroma cacao tree. The beans are separated from the husk, fermented for up to seven days, then dried, ground, have their "nibs" removed (sounds painful!), and are liquified. The cocoa butter and chocolate liquor produced from all this work are what go into making chocolate.
But we are not done yet! The chocolate liquor and cocoa butter are mixed with other ingredients (such as sugar, milk solids, and vanilla) and blended together for up to a month! Only then are we near the lovely food we call chocolate.
Because both the beans and the processing vary from region to region and "house" to "house" (chocolate manufacturers are call "houses"), there is a wide variety available in taste and texture of different chocolates.
Chocolate has long been considered an aphrodisiac, and there is some truth to this. The substance phenylethylamine has been linked to production of the same state we feel when we fall in love. Add that to the caffeine (a stimulant) and the tryptophan (a serotonin inducer related to good moods) and you can see why people might link it to arousal! Chocolate, also, has long been linked to romance and love, so the psychology is there as well.
More recently chocolate has been in the news as a potentially beneficial substance for lowering blood pressure. Evidence suggests that a small amount of chocolate eaten each day can aid in lowering blood pressure and in heart health. An interesting side note to this: in Oriental Medicine, the flavor "bitter" is supposed to affect the heart, and bitter is considered to promote heart health.
But neither of these is great news for lovers of white chocolate, or even milk chocolate. The main benefits and effects are attributed only to dark chocolate. So sorry for the sweet lovers...
We are quite lucky in this area (and in the US in general). There are a great many chocolate shops around. If you are a fan of chocolates, you should definitely try some different varieties to see what best suits your personal tastes.
Some of my favorites locally are:
Piece, Love, and Chocolate - located near the Pearl Street Mall in Boulder, they sell a wide variety of different chocolates from different vendors as well as their own stuff.
Ritual Chocolate - located in Denver, but available at Cafe Sole in Boulder, they sell a lovely single source bar. You should really try it!