I'll split up my response at various price points.

Luxury Cuvees

If you ever see it, do not hesitate to try any vintage of Bollinger Vielles Vignes Francaises. At a comparative tasting, it beat out Pol Roger P.R. Reserve Special, Krug Grande Cuvee, Louis Roederer Cristal, Bollinger R.D. and Louis Roederer Cristal Rose. I have been lucky enough to try three different vintages of it and it is always stunning. The only problem is that not only is it the rarest luxury cuvee out there, it is certainly the most expensive. In any given year there are only about 2,000 bottles. After that I would suggest Vintage Krug with enough bottle age. As Krug does not undergo a malo-lactic fermentation, it needs time to develop. For those with sufficient cash, consider Krug Collection. Third place goes to Bollinger R.D. and it is a wonderful meal time champagne. I had a bottle of the Bollinger R.D. 1990 on Christmas Eve. Excellent balance, big in the mouth and oaky.

Past disappointments include Veuve Clicquot La Grande Dame Rose, Salon, Taittinger Comtes de Champagne and Laurent Perrier Cuvee Grande Siecle but I am always willing to try them again to see if they have changed.

Vintage Champagnes

Bollinger Grande Annee with at least 10 years bottle age. Pol Roger's Blanc de Chardonnay and Pol Roger's Rose. Drink the Rose on release but the Chardonnay can age. Much better value for money than Salon.

Non-vintage cuvees

My first choice for a rose would be Laurent Perrier's Rose. This is made by skin contact rather than by blending red and white juice. I have heard very good reviews of the Billecart Salmon Rose but sadly have never tried it.

For a straigh non-vintage champagne, my most recent pleasant memory was of Piper-Heidsieck. According to critics, Charles Heidsieck has made a big jump in quality over the last few years. Again one that I must try.

California

Roederer Estate is very good but in Ontario, Canada at least, it is a bit pricey.

Loire

Consider trying a Chenin Blanc based sparkler from the Loire valley.

I hope this helps.