You guys are missing the best cupcakes. They don't have a storefront, they are only catering, but they are awesome.
My favorite cupcakes in Miami are from Cupcakes Nouveau, www.cupcakesnouveau.com. I first tried their cupcakes at a friend's baby shower and I had to order them myself. I have ordered from them twice so far and the flavor and presentation is always fantastic. They have some beautiful pictures on flikr, http://www.flickr.com/photos/24208511@N03/.