For the extra outlay, you get more in the way of 'complications,' the watchmaker's term for any function beyond displaying the seconds, minutes and hours. The most common and useful are the ability to display the date, followed by day of the week, month and year. The most popular functions among collectors are dual time-zones, moon-phases andchronographs. It's a given that the cases will be gold or platinum. Above this, where the cognoscenti prowl, prices reach six figures for perpetual calendars,tourbillons and minute repeaters.