my space is 6ft x 3ft, see here:
http://thehotpepper.com/topic/56170-keeping-insects-out-indoor-grow/?p=1201578
I have a single 400w Apollo dim-able ballast and chepo wing reflector; it's currently running a Metal Halide bulb at 75% power. This thing is super bright, maybe too much so for my 3-4" seedlings! Got this brand new on ebay for $95 shipped, the whole kit (hanging cord system, reflector, digital ballast and MH bulb).
On the seed starting side (right side of grow area in pic) there is a 2 ft 4 bulb T5 HO florescent fixture I got from Amazon for $55 shipped, this included bulbs.
This light seems to work really nice for starting seeds but 15-20 solo cups is maximum for a 2ft fixture since I like to have the fixture about 1" above the plant. I had a single 5 gal jalapeno under this light for several months and it did OK, about 15 pods but has since been kicked outside, see above pic.
When my seedlings get potted up to 5gal buckets, I plan on removing the T5 fixture on the right and buying another identical 400w HID setup; just with a HPS bulb.
So, I'll have a total of 800w of light from 2 HID ballast, one with MH bulb, the other with HPS. This should give me nice spectrum coverage.
For the a $200 price, and considering 3 peppers, 7 tomatoes I wanted plenty of light; hopefully the 800w HID will deliver.
I would recommend HID due to cost of purchase and how much light they can emit.
I'm also thinking that come December, January the heat generated by an HID will help to warm my basement grow area when it's 0 deg. outside.
But, I am a complete newb, I'm just starting so I could be totally wrong; time will tell.