If heat and lack of ventilation are a problem, you could look into compact fluorescents. This seems to be a growing trend among many closet growers. I prefer them for rooting seedlings/clones, but it is possible use them throughout all the stages of growth.

If you're only growing two plants, you could get by with fluorescents alone...but your yield will probably be diminished compared to what you would have gotten out of a 600-watt HPS or MH. HPS being your best bet for veg & flowering stages.

Good luck! :rastasmoke: