I see the following fans in your pictures if I'm not mistaken:
(1) PSU (120mm)
(1) 120mm top of case
(1) 120mm Back of case behind CPU
(1) 70-ish(?) back of case above lower SLI Card
(3) on your radiator
(1) in front of your power supply
(1) in the front of the case
If your system is quiet, I recommend you seek out the nearest otologist ASAP.
I have Antec 3 fans in another system using a P180 case and know for a fact that, even on low settings, they are anything BUT silent...
you need to invest in better fans and a fan controller
As of today
PSU - 140MM Yate Loon medium speed
1 SilenX 120 x 38mm top of case
1 Silenx 120 x 38mm back of case
60x38 is no longer there, was just trying something
3 SilenX 120 x 38mm on rad
1 SilenX 120 x 38mm in front of power supply
1 SilenX 120 x 38mm in front of case
1 Rheobus usually only feeding 7V to 120mm fans and about 10v to 140mm fan.
SilenX fans are 18dB 90cfm, but at 6v are inaudible
I run 4ghz on the E8400 and 725/2000/1850 on the 8800GTs with the fans on 1/3 turn up and it's fine playing crysis for hours on end. If you listen really close when the fans are turned down you can barely hear the pump even though its on a petra's gel mat. My system is near silent unless I'm benching or crunching and have the fans turned up then you can hear a little wind noise through the rad, but no fan blade or mechanical noise. I have an insulated P180, this insulation
http://www.svc.com/apapd.html, but the pump noise comes through the front fan as the pump is right behind it, even though the door is insulated as well. The pump will be moved in the near future though. With the fans on high its completely stable at 4.5gz and meaner clocks on the 8800s and it is a litte noisy, but nothing is like a antec 3s.
Pardon my ghetto masking tape, as you can see where the 60mm fan was is now blocked off, I'm experimenting trying to get the flow just right then I'll cut some lexan.
The antec 3 fans SUCK. How do I know?
Here took them out of the box for you (all 120mm fans: antec 3 38mm, antec 3 25mm, evercool 25mm, few different flavors of yate loon 25mm, silverstone 25mm, aerocool 25mm, thermaltake 25mm, and sflex 25mm)