Given the funds, I'd follow the example of Lily Bollinger, who said in 1961: "I only drink champagne when I'm happy and when I'm sad. Sometimes I drink it when I'm alone. When I have company I consider it obligatory. I trifle with it if I'm not in a hurry and drink it when I am, otherwise I never touch the stuff unless I am thirsty."
Money is the main reason I don't have a bottle of Bolly or Billy (Billecart-Salmon) to hand at all times, although this champagne socialist is not about to quibble with the prices of the best bottles because so few producers manage to master the magical mix of electric tingle, patisserie richness and caressing mousse of good champagne.
For most of us most of the time, however, 40 quid (let alone 90) is hard to justify for a single bottle (although I've spent more than the £40 case-deal price Majestic has for Bollinger Special Cuvée NV on football tickets and had less fun). Fortunately, the distance between champagne and the cheaper alternatives has narrowed in recent years.
These rivals tend to fall into two camps. The first and biggest is made up of producers inspired by champagne, using the same grape varieties and methods. I'd count Italy's Franciacorta (Ca' del Bosco, Berlucchi, Ferrari), the US (Louis Roederer Quartet from the champagne house's California operation) and, particularly, England (Nyetimber, Ridgeview, Gusbourne, Coates & Seely). The best now offer serious competition to champagne in the £20-£30 bracket, although some are priced much higher.
Under £20, when most champagne is joyless (although look out for Christmas deals on own-labels such as Tesco Finest Premier Cru NV, Sainsbury's Blanc de Noirs NV and the Co-operative's Les Pionniers NV), the southern hemisphere offers the best champagne-alikes. Try Jansz NV from Tasmania (£15.25, Oddbins), New Zealand's Cloudy Bay Pelorus NV (£15.98 if you buy two bottles, Majestic), Jacob's Creek Chardonnay Pinot Noir Brut South East Australia NV (£10.39, widely available) and South Africa's Rhona Brut Rosé NV (£13.99, Marks & Spencer).
In many ways it's the second group – sparkling wines that don't try slavishly to imitate champagne – that make for better buys. France has the crisp apple bite of sparkling chenin blanc from the Loire, for example, and Spanish Cava always seems more interesting when it sticks to native varieties macabeo, parellada and xarel-lo rather than champagne's chardonnay or pinot noir (Tesco's Cava Brut at £4.99 is great value; Gramona's Gran Reserva III Lustros 2004 – £28.95, bbr.com, delicious).
But it's Italy's idiosyncratic selection that offers the most intriguing alternative fizz, and not just easy, frivolous prosecco like Col Vetoraz Spumante Extra Dry (£11.59, fortyfiveten.com). Wines such as the sweet, sparkling moscato of M&S Asti Spumante NV (£7.99) or, even better, the gently effervescent Cerutti Suri Sandrinet Moscato d'Asti 2012 (£11.95, bbr.com), the brisk cherry-filled Martino Zanetti Wildbacher Brut Rosé from the Veneto (£16, batwine.co.uk), or the bubbling black fruit of red Becco Rosso Lambrusco di Castelvetro (£12.50, vini-italiani.co.uk) have little in common with champagne apart from the fizz. While I might not drink them all the time, they'll do very well when I'm happy. Or sad. Or thirsty.
Six of the best for Christmas fizz
Côté Mas Piquepoul Frisant, Languedoc, France NV (£9.45, Jeroboams)
Jean-Claude Mas has tried his hand at pretty much every other style at his prolific Languedoc operation, so it was only a matter of time before he started making a fizz. Using the bright, pear-scented, dry white wine of Picpoul as a base, he's come up with a southern French take on Prosecco: light, sherbet-frothy and fun.
Casa Coste Piane Prosecco di Valdobbiadene sur Lie Frizzante, Veneto, Italy NV(£16, vini-italiani.co.uk)
To borrow from the language of beer, this is craft – rather than lager-like industrial –prosecco. Made on a small-scale, it's bottle-fermented and, like bottle-conditioned ales, the yeast left in the bottle makes it a little cloudy. Its taste and texture are also in a different league: soft and graceful, with notes of honey, fresh apple and citrus peel.
Domaine de la Taille aux Loups Triple Zero Montlouis Petillant NV (£17.50, Oddbins; Justerini & Brooks)
The "Triple Zero" refers to the winemaking process – Loire winemaker Jacky Blot has refrained from adding sugarat any point from harvest to bottling – but it also sums up the style of this very dry but never austere fizz, where the sheer clarity of the apple fruit and the purity of the fluent acidity is simply exhilarating.
Gusbourne Estate Blanc de Blancs, Kent, England 2009 (from £29.99 Armit; Selfridges; The Secret Cellar)
My current favourite English fizz – and it's a sign of how far the native industry has come in the past few years that it's now a hotly contested category – Gusbourne's all-chardonnay cuvee from Appledore in Kent has that distinctive English chime of Cox's apple-like acidity providing the backdrop to the nutty pastry, riper golden apples and creamy mousse.
Charles Heidsieck Brut Réserve Champagne, France NV (from £36, Exel Wines; Fortnum & Mason; Selfridges; Harrods; Harperwells; Hedonism Wines; Philglas & Swiggot; Corks Out; Wined Up Here)
Not just the best of the champagne brands with Heidsieck in their name, Charles is currently making some of the best non-vintage champagnes full stop. This is fabulously rich and biscuity but harmonious, its vanilla creamy intensity illuminated by the fine streak of acidity.
Egly-Ouriet Blanc de Noirs Vieilles Vignes Brut Grand Cru Ambonay, Champagne, France (from £89, Lea & Sandeman, Roberson, Corney & Barrow, Berry Bros & Rudd)
A leading light of Champagne's grower movement (where the wines are made by the same small producer that grew the grapes), Egly-Ouriet's luminous white fizz made from pinot noir grown in the top grand cru village of Ambonay is one of the world's great wines: refined and graceful in texture, complex in its layering of baked bread and pure apple and fruit flavours, and sparkling and crackling with energy.
