One of many bars, taverns, restaurants and saloons billing itself as the oldest bar in New York, the Ear Inn is one of only a few that have been designated as a historical landmark and won the right of protection from future developers. When it was built in 1817, the Manhattan shoreline was only five feet from the bar entrance, and the place made its first fortune serving seamen and ruffians. Despite the age and the ever-present, self-conscious sense of history, the Ear Inn retains a lot of that residual blue-collar charm. Lunch and happy hours are dominated by a colorful crowd of brawny workingmen, and the yuppies arriving later are a small, self-selecting group that does nothing to diminish the atmosphere. Food is cheap and commendable; entertainment -- live music and sometimes poets -- satisfying.