I've made this recipe before that went along with a carrot cake. The cake was a bit dense, but the icing had very good flavor. Make sure to use real vanilla extract and not the imitation stuff. I suppose you can adjust the fluffiness of the icing by giving it some speed time with a KitchenAid to drive more air into the mixture.
Source:
http://www.foodnetwork.com/food/recipes/recipe/0,1977,FOOD_9936_29955,00.html
Cream Cheese Frosting
8 ounces cream cheese
2 ounces unsalted butter, room temperature
1 teaspoon vanilla extract
9 ounces powdered sugar, sifted, approximately 2 cups
In the bowl of a stand mixer with paddle attachment, combine the cream cheese and butter on medium just until blended. Add the vanilla and beat until combined. With the speed on low, add the powdered sugar in 4 batches and beat until smooth between each addition.
Place the frosting in the refrigerator for 5 to 10 minutes before using.