i've just had all 4 sit on High.
The Antec Nine Hundred has two 120mm fans mounted at the lower front f the case, a 200mm fan on the top of the case, at the rear (where a PSU would normally go. The PSU is mounted at the bottom), and a 120mm fan at the rear top. I have just a lame CPU fan (probably 92mm or whatever), and a 120mm fan on my PSU. The PSU is mounted upside down, due the the case having the PSU mounted on the bottom.
What would be the best way to keep a video card cool? I can install two more 120mm fans (On the side of the case, and there is a mount on the back of the drive cage thing for one), but would prefer not to. I'm in debt already.