There are many interesting coins of the United States and some are not well-known. That list would have to include the copper-nickel three-cent piece, which at least for a brief time was a very important coin in circulation.
In terms of prices, key coins sometimes seem to have a life of their own. The list of key coins that are, at least in some grades, more expensive than their numbers at grading services would suggest is long. To this group can be added the 1911-D Indian Head quarter eagle.
Generation after generation has come to the same basic conclusion that the Lincoln cent is a great collection. There is really no dispute that now approaching the century mark in terms of production when you look at a Lincoln cent collection you will find virtually everything you could ever want in a collection with the possible exception of the great rarity. There are key dates, semi-key dates and plenty of available dates as well.
There is no doubt that Walking Liberty half dollars are a very popular collection. Certainly at least part of their popularity comes from a design that can safely be called an American classic. A good design, however, does not by definition mean popularity.