Rig built, but noisy - seeking advice on *low noise* cooling

[rollercoaster]

My new rig:
AMD 3700+ and stock fan.
ASUS A8N-E mobo
Seasonic S-12 500 PSU
XFX 7800GT card
Thermaltake SHARK case with stock 120mm intake and exhaust
Samsung Spinpoint SATA 200GB

The rig works very nicely. But it is noisy and it is not just coming from
the gfx card. I have covered the side vent on the SHARK case with
plexiglass. I have 100USD to spend on making it more quiet. I do not
want to even try unless I can get significant noise reduction.

As I see it I have two options:
1. Replace stock fans with low noise versions and add sound insulation
foam to case.
2. Go to liquid cooling.

Any comments regarding these options? I think option 2 is not practical
given the budget

Regarding option 1, can anybody comment if the Zalman CPU and GPU
coolers are much more quiet that the stock ones? I find the case fans
pretty noisy, are the Nexus 120mm quiet fans really much quiter?

Finally, my rig runs super cool at the moment as all fans are on full
speed. Idle temps are CPU=23C, MB=21C and GPU=33. When playing
hours of BF2 the CPU&GPU temperatures rise by only 15C. Is it worth to
try slowing down the different fans? What is a good solution for that?

Any comments on AMDs Cool'nQuiet?

Many thanks for any of your comment!

 

[Athloniac]

a little device like a zalman fanmate is the cheap and simple solution for noisy coolers. but your temps will rise a little.

 

[bront]

What's making all the noise?

I made sure to get a PSU that had a 120 MM fan, and that helps a lot. The noisiest component in my case is the video card (same one you have).

I'd look into potentialy replacing the Video card fan, or perhaps see if you can turn down the 2 case fans. It realy depends on what's making the noise.