Well mine is slightly different as I have a 360 rad in the roof with some panaflo fans on it.
BUT if I was going air cooling, obviously leave the big fan in the front as an intake and I'd put another 120mm fan on the floor where the grill is by the PSU as an intake.
Then I'd either (depending on cooler) have the fan on the back of the case near the CPU as an intake and just leave the two 230mm fans on top of the case as outtakes OR have all three up top as outs.