I have the CIT 1012 case which has space for 4 fans (one of which is unusable due to the RESET switch and wires in the way)

Which is the best way to set up my fans for optimal cooling?

Currently:
1x80mm Rear fan on exhaust - air out
1x80mm Upper Side (CPU) fan on exhaust - air out
1x120mm Lower Side (GPU) fan on intake - air in (mainly because I read that my HD 4870 tends to get quite hot under load.)

I'm pretty sure the only fan on my PSU is at the rear, if it helps

Does it all seem logical? or is it best to have both my side fans on intake?