If you're going to splash out on Champers, don't be fooled into thinking that brands like Moet and Lanson are good.
For those with a more discerning palate, you cannot beat Veuve Clicquot, Perrier Jouet and Laurent Perrier (all retailing between £38.99 and £34.99). Monopole rosé is like strawberries and cream in a glass and is often available for as little as £19.99.
If you really want to splash out, try Perrier Jouet La Belle Epoque (about £65 from all good wine stockists), Veuve Clicquot Le Grande Dame (£55 upwards) or splash out around £95 for a bottle of Krug.
If you want a nice wine, you cannot beat a good Sancerre. There's a new breed of blush Sancerre - I think Tesco are doing one for under £14. A fine Montrachet would set you back anything between £25 and £65, depending on the quality.
Hope that helps.