Everybody has different setups. Some use flouro tubes or CFL or both, some (like me) have HID MH/HPS lights. HID lights are ideal because they give you the most lumens per watt. Flouros and CFL's can't penetrate canopies like HID. Bottom line, people do with what they have. It's amazing what a little know-how and creativity will accomplish. Some of the guys on this site have really interesting grow ops.