I have never had a bellini. I am going to have to add that to my "alcoholic drinks to try" list.
They're traditionally made with peach "nectar" (puree/juice), but my mom and I love mango, so I made it with that instead.
The best is the Cipriani bellini mix, you can get it in speciality supermarkets. It's from the NY restaurant that is owned by the guy who created bellinis in Italy. It's white peach puree. All of the Looza puree/juices are also really good with champagne.