This is on my list of things to do this Summer! First, I have to find sport bras that fit --nearly impossible for me. There is the issue of width in the cup -- not just depth -- that I have to consider.
I've always worn nude and black bras only, and I favor the Invisible Edge panties from Soma. I have been trying some of the prints lately (I know, really partying hard, aren't I?) and I like the dots and the animal prints that harmonize with my bras.
I think with your change in lifestyle, it's a great time to have more fun with your "first layer." It might help you enjoy a more casual wardrobe, too!