I have not deviated from the Wilton icing recipe because that is what I learned from and I only make my family about 1 cake a month. I occasionally bring a cake to work and they like the buttercream just fine. I am now bored with it and figure I should expand my horizons and try something else.

My question is how would I change the consistency? I was taught that icing a cake should have thin consistency, borders should have another consistency and flowers another. I am a "go by the recipe" kind of gal, so I need to know if just simply adding water or confectioners sugar would do the trick if I just picked another recipe to try.

Can you give me some different recipes to try that are proven winners?

Do you use the class recipe or the website recipe with the butter? I used the class for class only and when I make icing for my own use it's 1/2 butter and 1/2 shortening. I always make a double batch and for flavoring instead of 2t of clear vanilla I use 1t vanilla, 1/2t clear butter flavor and 1/2t almond flavor with a pinch of salt. I like to use heavy cream to thin my icing or occasionally corn syrup. As far as the amount of liquid I just eyeball it.
My sister in law likes a richer flavored icing so for her cakes I use 1/2 shortening, 1/4 butter, and 1/4 cream cheese and thin with heavy cream. The cream cheese adds a subtle richness to the icing.
For a different recipe I've heard good things about IMBC but I'm waiting for cooler weather to give that a try. That recipe is available on this site.
Have fun experimenting!