If you're going to buy a new fixture or even piece one together I'd urge you to pass on PCs. T5HOs are way more efficient in terms of light output per watt of energy used, the bulbs are cheaper and last alot longer. PCs are old technology. If you have 'em use 'em and conversion bulbs are a good option if you have an incandescent fixture and don't want to scrap it, but even if you get the fixture for free it won't take too many years until the cost of bulb replacement has made you spend more than you would have buying a T5 fixture and the replacement bulbs it needs.