I'd use a 400 watt lamp, but it's hard to tell you exactly what to use, because we don't know how much heat will be generated in your closet from whatever light you decide to put in it. However, it seems like your closet is small and therefore you can't put a light in it that is too hot. If you don't have proper ventilation, even a 400 watt lamp can over-heat your closet.
Fluorescent lights are nice, because they don't get near as hot as HIDs and you can bring them in close to your plants. Unless your closet can't handle the heat, it is advised to use HPS for flowering. However, you can get nice buds using only fluorescent bulbs, but the buds won't be as big, or as numerous.