1) i dont like the idea of bringing air in past the radiator heating it , and then heating up all the "rest of the stuff" on the motherboard with it.
keep remembering that water cooling is only specific components, and can be ignoring something that can be hotter than what your water cooling.
they have awesome coverage motherboard chipset water coolers , but they cant cover everything.
2) the heat leaving the PSU is going to go back into any close suction point. especially the higher ones. in your picture depending on clearance and all the psu heat is going to loop right back into the case. and going to be warming the air going past the radiator.
3) heat rises, cold drops (however you want to say it) , even if it (kind of) pools and mixes and is more like a floating cloud , than a river.
so exit air should generally depart upward. out with the hot, in with the cold.
You have that covered with the top fan. not much of the hot air exiting out the top is going to loop back around into the case.
4) in the front you have a low intake, which should be good for cooling the hard drives, and (so far) will have minimal warm air mixing in and heading to that. so that looks good too.
when you do the pic in photoshop, color code the arrows
for hot flow , and cold flow, it will improve your photoshop skills
with fan size the ideas and pictures can be somewhat decieving, for me i figure more like "a fan is a fan" 80mm ones were higher RPM, and 240s were lower RPM, the smaller faster fans at higher RPM are similar pressure relative too. so When big is to reduce RPM and noise, "a fan is a fan".
The only time that changes a lot is when "a Mega fan is a Mega fan", high rpm for its size, is more like 2 fans.
so a big fat hole with a slow moving fan that is Very quiet, is similar to a Smaller hole with a little screamer in it, when it comes to general flow and pressure, even if the CFM numbers might be a lot different.
if you put some mighty fans on the radiator? to get some good flow going there, or are using fans that push a lot of CMF at "pressure" that hole could be a lot of air flow.
PSUs are increasing in efficency, and the percentage of Waste in the form of heat, is not as high as it was. especially with these bronze and gold efficency rated psus.
also many of them now have thermal fan control, the temperature of the air is about the same, but the quantity of air movement is lower.
.
