LEDs would be good but you may run into some height restrictions. The Blackstars are normally run around 15 - 20" above the plants in veg and 10 - 12" during flowering. You can run them lower but your node spacing will be tighter, which may not necessarily be a bad thing given the height of your box. CFLs will allow you to keep the lights a lot closer to the plants but they will generate more heat than the LEDs. If you do buy a BS, I'd recommend the 240 watt model for your space.