The types of exercises you do should be balanced between upper and lower body work so that you don't get out of proportion.
Usually weight training will enhance what you have. not detract from it, though if you get very lean you may lose some curves that you have due to low bodyfat. Think about gymnasts and how narrow their hips become. Then again, look at figure competitors - they are fairly lean and have great figures.
-------------- Argue for your limitations, and sure enough, they\'re yours.
Richard Bach