Whatever you go with, AVOID the two-tube 4' flourescents in the huge end displays at the big box stores like the plague. As already mentioned, they are noisy, and won't fully light in cool temperatures. Plus, they are of poor quality and you will be replacing ballasts more often than lamps. You will be lucky to have 75% of them light up when you flip the switch. Try to buy a decent brand like Lithonia. Expect to spend about $30 per fixture. The money you save on cheaper fixtures goes right out the window when you have to keep swapping ballasts to keep them alive.