I just bought two new fans for my case, one's a 80mm aluminium cooler from Titan, and the other is a 120mm thermalkiller from Chieftec.

I replaced the stock intake fan with the aluminium, and also the back. The way I bought them was pretty funny, I walked into a computer store and asked for fans with low noise production, the store staff didn't really know also, so they just took every possible 80 and 120mm fan they had and connected them for me so I could hear for myself.

These are my current temps taken from ASUS Probe and Nvidia panel

CPU - 30 Idle, 42 Stressed (Half Life 2)
MB - 20
GC -48

The air coming from the Titan Cooler is pretty darn cold when I hold my hand in front of it.

Noise reduction was not less though, only after I turn the speed of my cpu cooler down.