I definitely flavor my icing, and sometimes my dough as well. As Susan mentioned, I am a big fan of the all-natural flavorings from Spices Etc. Too many to list, but off the top of my head, Coconut, Lime, Orange, Pomegranate, Raspberry, Lemon and the can't-do-without Clear Vanilla pop into mind, With Fall here, I am using Pumpkin Pie Spice, Brown Sugar and Maple (Yum!!). Adding Chocolate to my chocolate dough was just the touch it needed. Perfect and tons of compliments.
If you want it, here is a discount code you can use for a first time order:
CC9 flat rate shipping of $4.95 for orders within the US only
AKT9 15% for US or international orders (discount taken before shipping costs)
Choose the one code that applies to you or what you want and enter it at the beginning of checkout and then continue on.
Here is a link to their flavorings and extracts page as well:
Hope that helps out! I love the variety that they have given to my repertoire!