Looks like I'm late to the party. I recall my 180b coming with three stock 120mm. One at the top, one at the top rear, and I can't remember stock placement of the third. All together, there are 6 possible mount locations (which I think have been covered; two by the front air filters, one optional mount to the rear of the top HD cage, one mount position by the PSU, then the two near the top rear of the case). I personally run two of my fans at the top and top rear, with the third attached to the "back" of the top hard drive cage, blowing right on my two passively cooled graphics cards. I probably should get a few fans for the front panel to increase the air flow pressure to something a bit more positive <.<