Hi Sharker, welcome to the Planted Tank!
What are the dimensions of your tank? If it is 18" deep, placing one row of PC lights over it will lead to some uneven lighting!
Using two rows of 55W lights you get into that high-light, high-maintenance thing, where you need CO2 and regular fertilizer dosing.
If that isn't your thing, you might look into regular 4 feet fluorescents. They are cool and cheap, and provide a more evenly distributed light. On the downside, it is hard to get good reflectors for them.
My personal favorite solution? For a low light tank, put three T5 bulbs with individual reflectors over it. For a high light tank, three HO T5 bulbs with individual reflectors. This isn't cheap, but bright and very energy efficient, if you are concerned about that.