Naomi Campbell once claimed to have perfect-sized breasts. Not too big and not too small, her supermodel orbs were just large enough to fit into a vintage champagne coupe, she said, with no unsightly overspill. You and I would call that a B-cup, but Campbell’s assessment of her assets, although not scientific, makes that modest measure sound like the most decadent thing in the world. You wonder who first thought of using a champagne glass as a bosom gauge. Was it Toulouse-Lautrec attempting to distinguish between one cancan girl and another? Perhaps Josephine Baker introduced it at a bohemian 1920s party.

One thing is for sure: nobody would ever measure perfection like that today. These days, breast size, like everything else, is subject to inflation. Gone are the days when anything more than a handful was considered a waste. Big is better — Cheryl Cole’s 28F delights were recently voted the best boobs in showbiz, making Naomi’s little champagne coupes appear disappointingly restrained by comparison.

How did it come to this? How have we forgotten the beauty of a moderate, manageable amount? When it comes to figures, Cole’s or other sorts, it’s all about extremes. We like to hear of incomprehensibly huge numbers — the ever-increasing trillions of US national debt, the £500 billion UK bank bail-out, Damien Hirst’s £100m art sale — or terrifyingly small ones (£3 jeans and 99p flights). Everything in between is ignored or dismissed as dull. But look where this obsession with extremes has got us — economic meltdown, financial catastrophe, recession, depression. And are we happy?

I can’t help but think that if everyone had stuck to a moderate spending limit over the past few years, we wouldn’t be in the financial mess we are now. But what does moderate mean? For me, somewhere in the region of £250 is the perfect amount of cash, because it’s a spoiling without being ruinous.

So many of life’s finer things can be had for exactly that amount. If you went to the theatre, you would be sitting in some of the best seats in the house. The tasting menu at Heston Blumenthal’s Fat Duck restaurant, in Bray, is £250 for two (although you’ll have to get your date to chip in for the wine, which is extra). For £250, you could enjoy a filthy night of lust in a luxury hotel (Claridge’s has rooms from £199).

Or you could seduce in the comfort of your own home using a Kiki de Montparnasse quarter-cup bra and matching knickers as your weapon of choice (£109 each, from The Shop at Bluebird). You could get tipsy in style on vintage champagne — a bottle of Krug 1995 costs £189 at Oddbins, which would leave you more than enough for a packet of Alka-Seltzer.

Even diamonds are within reach. I’m not talking about the nasty supermarket variety, but chic, interesting diamonds. Astley Clarke has an 18ct-gold Gatsby ring, set with not one but two cognac-coloured diamonds, for £250. All right, they don’t match up to the indecently large rocks sported by such icons of the bigger-is-better culture as Victoria Beckham or Mariah Carey, but they are wonderfully charming.

It’s all too easy to fixate on what £250 can’t buy you, rather than what it can. Houses, yachts and a week in the Maldives are out. And you’d get laughed out of Selfridges if you tried to purchase a decent designer handbag for that amount. Such a modest sum will never get you an Aston Martin, not even on eBay. But it will buy you a razzy time in one at the racetrack (courtesy of Red Letter Days).

You can have the world for £250 — you just might have to give it back at the end of the day. Let’s raise a coupe to that.

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