I kept the top 230's there since they move a decent amount of air without hardly any noise. I just can't see 3 120's moving more air without getting noisy. Also, I put 2 Scythe S-Flex "E" fans on the optional HDD Fan Rack. I think it definitely helps with moving more air across the PCI slots. The bottom optional 120 fan mount I decided to pass on, because if you put a fan there, it prevents you from removing the dust filter under the PS, but this might not be a big deal if you put your PS upside down, so the fan is on the top. I have mine on the bottom because I have a wood floor, and there's plenty of space for it to suck up the cool air from below the bottom of the case. If I was on carpet, I'd flip the PS, or put the case on stilts.
My room is fairly warm (75-80F) but that beast of a case only gets about 3-5F warmer than the outside.