I was looking into lights and noticed a lot of controversy over which type of lighting is best. What makes LED better than HPS? What the fuck IS HPS lighting anyways? I understand all the shit about photosynthesis and the wavelengths of red and blue lights...but what is the difference between the red and blue lights? How are these lights compared to regular fluorescent lights? and lastly, what is best for a common grower.

1.) mainly energy efficiency.
2.) high pressure sodium.
3.) wavelengths, but I think you mean color temperature.
4.) color temperature.
5.) CFL's, if you want to step it up CFL's for veg. and HPS for fruiting.
6.) this should be in tgo.
7.) inb4lock.

There are essentially four ways of generating light.

1) Black-body radiation, like a filament in a light bulb. Heat it up and it'll glow.
2) Glow-in-the-dark shit. It absorbs energy, then slowly releases it in the form of light.
3) Ionizing gases. Knock an electron away from a nucleus, and it'll release light when it falls back.
4) LEDs and lasers. They work kind of like 3, but with solid semiconductors instead of gases. They typically release light on only one frequency.

Getting light from #1 isn't a good idea because most of the radiation is heat, not visible light.

Generating light via #3 is preferred because you can release light on only a few frequencies, and you can release a LOT of it. This is called high-intensity discharge, or HID lighting. HPS (high-pressure sodium) and MH (metal halide) lights are types of HID lighting. Efficiency is highest of any type of lighting.

LED lights aren't as bright or efficient, but because they only release light at one frequency, they can release light on only those frequencies used by plants. They aren't bright enough or cheap enough to use for growing plants effectively though.

Fluorescents are a combination of #3 and #2. Mercury vapor is made to release UV light, it hits the glow-in-the-dark lining of the tube, and releases visible light. It isn't quite as efficient as HID lighting, but it's cheaper and doesn't require as much energy to operate a light. Fluorescent lights aren't as bright as HID lights either.

Every serious grower uses HID lighting, because that'll generate the most light of any type of lamp, for the least amount of money. It also happens to be the most efficient type of lighting.