Variations include the "Old Fashioned" variety that is made with just peanuts and salt and the newer and more common variety that has sugar added. Additionally, both Old Fashioned and Sugar varieties come in both chunky and creamy stylesindicating the presence or absence of actual non-mashed peanut bits. It is also possible to get freshly ground Peanut Butter at most grocery stores, however, these are rarely as satisfying due to the fact that they usually contain almost no salt or way to much salt, but never the right amount of salt. (This last bit is a personal preference of this researcher - who has decided that the only Peanut Butter worth eating is the Old Fashioned Chunky kind that is mass produced.)
Peanut Butter can also easily qualify as a staple of the American diet. It would be a rare thing indeed to find a household that didn't have a supply on hand. And, pretty much everyone raised in America today grew up on a steady diet of Peanut Butter and jelly sandwhiches. Most parents know that when all else fails, your kid will readily eat Peanut Butter, which may explain why even the fanciest of restaurants also keep a supply on hand for just those sort of dietary emergencies. It is also extremely versatile and goes well with practically any food you can imagine (it is commonly eaten with apples and as a dip for celery)
Because of its high fat content and high protein content and the fact that it does not need to be refrigerated, it is the perfect food to take with you if you have to evacuate your home because of some natural disaster.
Some final notes: The oil in the Old Fashioned variety, since it is lacking in sugar, is not fixed and will settle out to the top of the jar. This will mean you will have to stir this type Peanut Butter before you use it. Also, if you are planning to make a PB&J (Peanut Butter and Jelly Sandwhich), try toasting the bread. The Peanut Butter will melt slightly and will taste delicious.