And don't be a dufus like I was if your cpu fan is really close to the case outlet fan reverse its direction too, that cost me 5C in prime 95 having two fams fighting one another.
I have read so many conflicting opinions on this. I plan to pull the air away from my XP120 when I set it up. I think that it will draw the cooler air up, and exhaust it out the back of the case. I believe Thermalright says either way is effective, so experimentation is the only way to know for sure.