CFL's are great, and with the right spectrum are perfect for growing.

I used 1 15 watt, yeah, just 15 watts to veg a 1 foot high plant, and it was fine, no stretching or anything.

Btw, incandesants dont promote vegative growth, only stem growth, but thats only in high, not thickness, so realy it promotes stretching and possibly the plant falling over, so incandesants are ultimatly useless.