In the world of Americana, nothing is as valuable as items from the Camelot period. Or used to be. Purveyors now say that the shine is off John F. Kennedy because buyers are aging and the market is flooded. Bill Panagopulos, president of Alexander Autographs, the big Americana auction house, saw the trend last month when JFK's 1960 campaign watch, expected to bring $100,000, was passed over by bidders. "Yup, JFK is definitely cooling off." Ditto for the once popular Ronald Reagan. There is hope, though. The dollar's drop has made autographs popular with Euros. "Items with appeal to foreigners are rocketing in price, while the bread-and-butter American autographs are good for lining bird cages," he says.