This is my first dual radiator build and wasn't sure how to approach the fan configuration.  I have a 360 on top, 360 in front, and a 120mm fan in the rear.  I currently have the front as intake, the top rad as exhaust, and rear fan as exhaust but this got me second guessing myself.  If there is negative pressure by exhausting more than I'm taking in, I'm afraid the system will just suck air from the wide open rear panel of the case, where there are no dust filters.  On the flip side, I was worried that if I have the top and front as intakes, the system wouldn't be able to exhaust fast enough with just a single fan and unrestricted back panel.
 
I'm leaning towards the latter but would like to get your opinions on the matter.