The Italian Margherita from the Tutto Italia kiosk in the World Showcase is one of my favorites.
I also like some of the specialty margaritas from La Cava del Tequila. The classic, the blood orange and the pomegranate are probably my favorites.
The Rose & Crown's single malt flight was nice, though the Lagavulin was incredibly smoky.
Some of the specialty drinks at Jellyrolls are very good, too. I have ordered something called a "Sweet Emotion" a few times while there even though I still don't know exactly what's in it. Cranberry juice and rum are two of maybe five or six components. I've also heard good things about their "Blue Suede Shoes" cocktail, but I haven't tried it.