It also depends on the strain on how little light you can get away with in veg.
You can always flood your veg area with lots of light and things will def work out, but if you control the environment in your veg area and dial it in to your strain you would be surprised what you can get away with.
Below is one of my bubblelicious mothers. She was grown from seed & broke surface on april 26 2009. Lighting started out @ like 10x 26w 5300k cfl's but was slowly reduced to what you see in the pic. area had 4 mothers until a few days ago. 4x26w 5300k's above the mothers & 2x26w 5300k above the huge tub of clones. Countless clones have already been taken from her. She has had 2x 26w fall and make there home inside of her for a few days a few weeks back and burn 1/4 of her on one side (over 100shoots = dust). Anyways I can't stress enough how important it is to dial into your strain's requirements.
4x26w 5300k's. (area is 3ftx3ft) (current pic)
Side view
Same area a few days back when there was 4x mothers w/ same lighting.