I went for the fan side of the psu facing down. There's a nice gap between the case floor and the psu cage - it just seemed to be the way to go.
As for the artic freezer, I went with rear of the freezer facing the rear of the case. The P182 has top and rear 120mm fans, so I figured there wasn't much to choose in terms of extraction. BUT... my mobo is an Abit IP35, and if I'd gone with "downward" orientation, the freezer's intake would be grabbing air heated by (1) the gfx card and (2) the chipset heatsinks. Finally, if I decide to mount a fan in the middle section of the case (in front of the middle HDD tray) then the freezer will get some of that fresh air...