Presumably, there will be earnest souls worrying over the great anxieties of the moment - global warming, crazed genetic experimentation, the rise of nationalism, the decline in morality, the crisis in the English novel - but, for most of us, the great millennial question will be rather more domestic. What the hell are we going to do on the night? If, traditionally, New Year's Eve is the most socially treacherous and anti-climactic night of the year, how can we avoid the risk being multiplied by a factor of 100, or even 1,000?
Already, certain twitchy, showy types have made their plans, booking tickets to flash foreign destinations with a view to celebrating the moment in a suitably boastful manner with cocktails on the slopes of Mount Kilaminjaro, a cruise on Lake Como or a party on the steps of the Taj Mahal. This is profoundly naff and reveals a deep inner insecurity. At some point, around 2003, they will look back on the money and effort they spent to mark a simple calendrical moment with quiet embarrassment.
In fact, the most interesting aspect of the next 99 days is how each of us will react to the imminent change of centuries. Like a grander, more prolonged version of this year's total eclipse, the way we behave between now and 31 December will provide a revealing test of personality. When the Moon obliterated the sun on 11 August, the emotionalists burst into tears and became humbly aware of the smallness of the human race in the great universal scheme of things and the paranoiacs made dramatic, life-changing decisions about love and work, while the inevitable gloom merchants pronounced the whole thing an over-hyped absurdity. Darkness? What on earth was all the fuss about? It happens every night, for heaven's sake.
So it will be over the coming weeks. Those who live in fear that life is passing them by will suddenly realise that an entire millennium has passed without their having quite the amount of irresponsible fun that they deserve, and will embark upon a frantic round of erotic, alcoholic and narcotic excess. The signs are already there, in clubs and pubs, on late-night Channel 4, the first rattling of the windows as Hurricane Hedonism approaches.
The more socially ambitious will soon be anxiously checking the morning's post for their invitation to the great dome party of 31 December. Already they dream of this great celebrity-fest - of chatting with Posh Beckham, of swapping jokes with Noel Edmonds, of running into Richard Branson in the Compassion Tent, of kissing the nearest person at midnight and discovering that it is Nicole Kidman.
The money-minded have already seen the night as a potential cash crop, with the humblest babysitter already being able to ask a fee for the night that would embarrass a top-class hooker. Musicians will particularly welcome the occasion. New Year's Eve has always been the night of the big bonus; this year's desperation for live music will encourage anyone who can master the chords of "Hi Ho Silver Lining", "Blue Suede Shoes" and "Auld Lang Syne" to dust off the guitar from the attic and make some pocket money for themselves.
The glums will already have decided to sleep the millennium in. They know that the television schedulers are planning to inflict on them a nightmarish line-up of the very personalities they would normally avoid - Chris Tarrant, Clive James, Geri Halliwell and Michael Buerk. They point out to anyone who will listen how odd and inappropriate it is for a secular society to celebrate a religious date with such godless abandon. For these people, talk of the millennium bug provides a grim satisfaction. As aeroplanes are plucked from the sky, banks' computer records are wiped overnight, telephone lines go dead, supermarkets close down and the whole of technology rises up in rebellion, they will be at home, under the duvet, safe in the knowledge that, over the previous months, they have been stocking up with tins, dried food and ready cash.
For each of us, these weeks will be a supreme test of character from which we will emerge in 100 days' time hung over, exhausted and perhaps slightly sheepish at the fuss we have been making. Then we will look round and discover that nothing has really changed except the date on the calendar.