I know the Night Blossom (non-alcoholic) is the most famous drink at Pongu Pongu in Pandora, but I had the Mo'ara Frozen Margarita and it was fabulous. It's a blood orange and strawberry margarita. I couldn't taste the tequila, but it was really good.
Here it is pictured with the Mo'ara High Country Ale. If you're a beer drinker, my boyfriend said it was also good.
I saw someone has already mentioned the frozen Grey Goose lemonade in the France pavilion at Epcot, but I can also vouch for that. There is an orange juice version that I did not try. My boyfriend and I split the drink; he said it was so good that he will order his own when we go back!
I believe they were about the same price, but you can see there is a huge difference in portion size. I will say, however, you can actually taste the alcohol in the frozen lemonade.
Those were the only frozen drinks I tried on my last trip. My sister-in-law swears that the La Cava Avocado Margarita from La Cava del Tequila in the Mexico pavilion is the best drink on Disney property. I didn't try it, but I plan on it this summer. You might want to give it a shot!