What kind of fabric should I use?

I am doing something a little different than I normally do so I was wondering what type of fabric would be best? I am making a Roman Goddess (Megara from Hercules) Costume for a little girl in size 3-4. I normally use high quality quilting cottons to make most of my dresses, but I think I will be needing something with a little more flow for this but have no idea what. Any suggestions are appreciated!