Veuve, PJ, and Piper H as PPs mentioned. All good. But don't get bubble for someone that doesn't love it, it's a waste of money. Seriously. My DH can't tel seltzer w/a splash of wine from Dom.
This is a good point. If there's something else you know they like to drink, you could also consider that. $100 will buy a very nice bottle of Scotch, or bourbon, or cognac, or cabernet ....
If it's just that champagne's traditional for celebrations, I'd stick in the $40-50 range, not spring the $100 for Dom.