It depends on the champagne. Some really benefit from opening up a bit, others do not. I would bet though it was shaped like a white wine glass, but had one important addition, the bottom of the glass was roughed up a bit (etched either mechanically or with an acid) to allow a place for bubbles to congregate and rise.

Many people argue that a white wine shaped glass is best (opening a bit smaller in diameter than the body of the glass) as it concentrates the flavors and aromas that the bubbles carry over a regular flute.

The only way to tell is to try it in a couple different kids of glass and see which you prefer (if there is a difference). Obviously the wine itself is the same, it's what the different glasses do to your perception of it, and how much of a factor surface area, etc is.