I'd say the Silent 775 should do good out of all the choices, besides the Zalman 9500.
Wow.. Although, looking at those pic's, you do have definate airflow problem. In your case I even see your PSU is going to re-introduce hot air back into the case, since you are using the exhaust fans as an intake, and nothing to really push it out, and bring in cool air. So it recirculating heat, unless your some how ducting that hot air away from the rear case fans, like I have been doing.
Since you don't have fans in the front, your not really able to push air out like my case is doing (including the side to push cool air in). I suppose the side case doesn't have a fan. You should be able to find somekind of mod kit to have one put on the side, or perhaps on the very top (meaning like where the PSU is like a blow hole on a whale).
I do see holes on the bottom of your case where the HD bay is, does your case have clearance underneth it? Might be able to mout a fan there to pull air up from the bottom of the case. Can't see into your bays to really tell if you can or cannot install fans in them.
I would put the exhaust fans back to push air out, and figure out something with that bottom vent, and maybe put a side fan on at the most. I'd also get a bunch of cable ties to get those power cords organized and tucked away from the MB.
If you put your DVD/CD-Rom on the middle bay, you can use that as a shelf to rest the cables when you cable tie them. Plus you might be able to install fans to push air directly to the CPU. (looks like it is in the line of site). Just an example:
5.25 Bay Fan
I know this is for HDs, but if you don't want to drill holes into the case, this may push some air into the front of the case to the CPU. It prolly will be noisy, and will not move air as good as 80mm fan. (80mm push at least 30CFM, while those push 20CMF, RPM are bit high, but they are small).
And if you go with that idea, you might want to get the IDE cable that is rounded instead of flat like you have that is on your DVD/CD-Rom drive. Or if you can manage to fold that cable neatly and push/tuck it aside. I think it will at least get air in, and the exhaust will help pull it in, while the HSF takes in it.
Just try to get you to imagine a way for air to get in, and get out. That last picture you did, still introduces heat from the PSU, and may cause a vacum lock to where air isn't flowing anywhere. But if you do place something inbetween, may help (plastic). Cardboard would eventually just bend, and to keep it in place, may be a pain.