Personally I think using a HPS (high pressure sodium) is the best way to go, these do however give off quite a bit of heat which means you would have to use some ventilation, opening the grow isn't a good idea as the smell is quite strong (especially in flowering) and it would be a sure fire way of getting caught, you can get a 250 watt HPS and get yourself a growtent these sometimes come with everything you need.
http://www.clevergreen.co.uk/shop/vclos ... 2268005505