I wouldn't go HID, but that's me. Just because you got a paycheck now, doesn't mean you want to ante up every month in electrical bills.
If you haven't ever grown before, a basic nutrient rich soil will be the most fool-proof, but Coco or Hydro would be the direction I'd go.
How much space do you have? Is it a medical grow? Do you have the time to put into 12x plants?
If you have the headroom (7-8ft), and want to run HID's, 3-4plants under a 600 can produce serious numbers. I've seen more than one good grower with a 600 outperform an average grower with a 1000, many times.
You have options...
3x IndaGrow pro420PAR (induction) lamps would pull about the same as 2x 600W HID's, but combined put out less than half the heat (ballast and bulb BTU's), would be more than plenty for 12 plants, and will last a LOT longer than an HID bulb (100K hrs vs 10K hrs).
LED I would look at California Light Works, Area 51, Black Dog, Apache Tech, or Astir's.
Do you know your kWh rates? That might help you make a decision.
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Run a perpetual setup, harvest more often and spend less time trimming(at a time).
4x clones/seedlings
4x Veggin
4x Flowering
Do it right, and that's 8-16zips per 45-50 days.