And it blows

My desktop PC is a noisy one. With a CPU fan speed of 3300+rpm, it was a pain to listen to. A few days ago I decided to try to reduce the sound as well as the CPU temperature. Thats when I realized that my front chassis fan (left picture, red arrow) was dead and the CPU was averaging 61-63C when idle. Hence I made a trip down to the store to get a new one.
Having obtained my new fan, firstly I had to adjust the CPU fan to lower speed if the target temperature is reached. This was done through the BIOS. Most new motherboards have this option (ASUS calls this Q-fan). Setting to 60% the full fan speed when the CPU target temperature is reached, and installing the new fan, I started the computer to get a new set of readings: fan speed of 2300+rpm and temperature of 56-58C.	"x" marks CPU fan blowing inwards
This was much quieter and cooler. However something seemed strange. Then I realized -- all fans were blowing into the chassis! After reading a some article somewhere on wikipedia, I adjusted my rear fans to direct exhaust air from the system. This should create air flow similar to the channels shown on the right.
Rebooting proved that having air flow from the bottom front to the top rear of the chassis is the best. When idle, the CPU temperature is 51-53C and the fan speed is ~1500rpm. A reduction of 10C and 1500+rpm respectively! Finally I can snooze comfortably with the PC on.