will any Flourescent light work or does it need to be a special one for growing?

Single tube kitchen lights are generally not worth a crap. The same goes for the small single tube floros you see sold at box stores labeled as grow lights and incandescents labeled as plant lights. All freaking junk that wont grow well.

A little floro edumacation:
With tube lights, the lower the number the better.
T12 = very poor lighting for the size bulb, very low lumen output
T8 = Slightly better, still not great
T5 = Now you are starting to get somewhere, more lumen output than both the others if using the same length bulb
T5HO = Best bang for the buck in tube floros. Double the wattage of a standard t5 with higher output. Reasonably affordable fixtures and bulbs.
T5Vho = Even higher output than t5ho. However they put off a good bit of heat and cost is much higher for fixtures and bulbs. Used more in salt water aquarium setups for live coral. Never see them mentioned on grow forums, i suspect that it is because by the time you consider cost hid is much cheaper.

If you only want to start one or two plants, some people use cfl. You want bright white or daylight bulbs for veg, not soft white. If on the package it has a k rating, such as 3000k, or 5500k then you want the higher number. This reflects the color spectrum as rated by the kelvin scale. Higher numbers are more blue spectrums and brighter light, like spring and summer. Lower numbers are closer to red and orange spectrums, like late summer and fall thus they are better for flower production. The color spectrum thing is true no matter what type of lighting regardless if it is cfl, t5, or hid.

If you want to start more than one or two plants i would recomend a t5ho setup. The more bulbs and larger size the better.

 

Best is a subjective term. They put off near as much heat as an hid setup, fixture prices are way too high, and in the end they dont have the penetration of hid lighting. Best of the floros sure but you might as well spend less for better lighting.

 

Great penetration compared to other floros yes but nothing like an hid. Even in reef tanks, past a certain depth they are ineffective and people that need more penetration go with hid lighting.

Spread out more or not doesnt really matter, heat is heat. The main cost comes with having to increase ventilation, which your going to have to do any way indoors. My t5vho fixtures had built in fans and would still get too hot to touch.

Yes you can get them much closer if your talking open reflectors. I can get my hid down to 12" away and still have canopy temps at 78. With good cooling, the couple of inches closer you can get the floros isnt enough to make more productive.

Im not saying they suck by any means, they are awesome floros. They have been around quite a while though, and if they were really the best in terms of yield vs time spent you would see large grow ops running huge rooms of them. However that just isnt the case.