Depends on how cool you want everything to run. Personally I use a lot of fans and prefer extra space between componets to increase air flow. Heat kills, my harddrives are spaced out and have a 120 mm fan blowing across them. From there I have 2 - 80 mm in the back, 1-80 in the side, 1 - 80 in the top, and then the fan in the power supply. I also have a zalman copper heatsink w/ 92 mm fan on the CPU. The processor stays nice n cool

As for noise it is really quite, none of the fans produce more then 25 dba. Y-adapters or the fan monitoring plugs on the Motherboard will work fine.