My guess would be to have them blowing out. From what I understand you want more fans pushing air out then in, since in the effort of pushing air out more will be pulled in. Or something like that. Not really sure. Hope it helps in the interim of someone educated in the subject answering.
Edit: In the designs I've seen there's generally air being pulled in from the front, sent across the components, then pushed out the sides and back panel.
yeah... usually the intake fans are towards the lowest areas of the case; front and side panel, colder air drawn in, rising to cool components as it heats up, then gets exhausted out at the nearest exhaust... plus ideally no conflict of airflow in this case usually... ...what also helps a great deal for cooling the cpu in particular, is to have an intake fan at the rear of the case, level with the cpu (even a 60mm, low rpm fan can make a large difference here), that way you get colder air blow directly onto the cpu heatsink from outside the case (noticable cpu temperature drop)... then the hotter air will be exhausted back out again when it reaches up to the psu just above at the top of the case
I highly advise against using the sidefans in a pull configuration. I modded my thermaltake soprano 92mm side fan into a 120mm fan . It works great, but i had my thermalright si-120 pulling air up directly to the 120mm side fan blowing out the case. all the fans in my case are thermaltake thunderblade 120mm fans that push 78cfm at 21db. they are very quiet, although for you silent users, you can hear the air moving. anyway, i had my fans pull out the back and the side. well, my motherboard, ram, cpu etc... was running quiet cool. One problem, the PSU. I choked it of air! i was sitting there one day and it actually shut off. I touch the back of the psu and it was hot to the touch. Its best to have your fans set like this:
Front: Pushing air into the case, recommend a high cfm fan (60+ cfm).
Rear: Pulling air out of the case, high flow fan (60+ cfm).
Side: Pushing air into the case, medium to high flow fan (40+ cfm)
Top: Pulling air out of the case, low to medium flow fan (30-50 cfm)
These are just my recommendations. I may be right I may be wrong, but it's what has worked great for me. These are based on 120mm fans. For 80mm Fans i would drop the cfm down by say 20-25cfm for noise sake.