This depends
How big is your space
What kind of enviro is in the grow space and the surrounding "building"
Are you training the plants
Growing from seed or clone
If you are trying for 6 plants I would go for the 600w hps, I have no personal experience with leds but they are a great option
Don"t forget an oscilating fan , a 8" table fan, depending on what style of growing a res and air pumps are needed for most teas and such for organic and soil media grows and all hydro systems
ph and ppm meters
room thermometer minimum 1, 4 is perfect (preferably one that has hummidity)
air scrubber / exhaust fan
In the top right corner is a button to the sponsor list.
I get most of my stuff from access hydro