Another vote for the P180. I had narrowed my choices down to pretty much the same ones listed above (P180, Stacker, Armor) and the P180 was the clear winner. The cooling in this case is phenomenal. The rear and top exhaust fans are positioned perfectly for cooling the CPU (and memory on my DFI board, since the mem slots are at the top). Pretty quiet too, considering the amount of overclocking I'm doing. If I was running at stock voltage, I would have both the fans on low and it would be practically silent.
With an Athlon X2 3800+ overclocked to 2.6 GHz (1.55v) and an XP120 HSF, I am able to keep my load temps below 49C with the rear fan on medium and the top fan on low. I couldn't fit the air duct for the video card because I'm using a V-1 cooler, so I can't comment on how well that works (although I don't need it - load temps are never above 65C on my O/Ced 6800GT).
I took the fan out of the bottom chamber and just use the PS fan, and that seems to work fine. It's a Seasonic S12-600, which fits perfectly and the cables reach (and the fan is silent). I mainly took the bottom fan out to make it easier to route power and SATA cables to my harddrives, but I really don't think it's needed because the SMART monitor for my harddrives shows the harddrive temp at 48C, which I don't think is too bad at all.