It all depends on your body size,shape and color. Not all colors go with all skin tones and not all dresses go with all body shapes that is why I can't tell you what color to wear. ( please be more specific) but I would stick with black just cause I like that color for dresses but it depends where you are going.
Like some people have said before, you can never go wrong with a little black dress. There are so many types of black dresses to choose from too, so no matter what shape, size or skin complexion you are... the black dress will work for you. DivaNY has really cute black dresses... you should check out their website: http://www.divany.com/index.php?cPath=1_24