I was wondering some information about case fans

1: Are all case fans the same? I know some of them have silent features but do they all cool the same?
2: Is ONE 120mm case fan better than TWO 80mm case fans?
3: How many fans are good/bad? For example: ONE 120mm in the front, ONE 120mm in the back and ONE 80mm in the side (and the heatsink fan)
4: Are all heatsink fans the same?
4a: Are all heaksinks the same?

You should have one fan in front blowing in cold air, one in the rear of the case blowing it out. I think that 120mm is a little over kill.

All heat sinks are not the same and neither are the fans for them. A good source for this is below:

http://www.coolerguys.com/cooling.html

Well could you give some recommendations on brands and models?

Here are a bunch of 80 mm case fans:

http://www.coolerguys.com/80.html

Here are some chipset heatsinks:

http://www.coolerguys.com/chipsetcooling.html

some noise conditioning stuff ( I hate a loud PC)

http://www.coolerguys.com/noisedampening.html

As far as the CPU heatsink and fan, you will have to know the make and model of the Processor.

Thermaltake is a good source as well:

http://thermaltakeusa.com/

Noctua NF-P12: Click here
Noctua NF-S12-800, NF-S12-1200 and NF-R8: Click here

Noctua is the brand to go with if you're looking for fans that are both silent and provide adequate air flow.

Regarding CPU fans, you can have a heatsink and have a fan that only pushes air through the heatsink fins. Or you can have one that pushes, and another on the otherside that pulls, which enables even more air to be moved across the fins.

Of course, you would need an exhaust fan to exhaust all the warm air out as well.

The set up in my case is currently one exhaust fan, one front intake fan, and I have my Arctic Cooling Freezer 7 Pro bringing air across the heatsink fins which is then removed by the exhaust.

The PSU fan also adds air exhaust.

+1 for the Noctua NF-P12 it has rubber grommets for lower noise as well as adapters if you don't want it a full speed. I would also recommend the Scythe S-Flex SFF21-E (1,200rpm) and SFF21-D (800rpm) series.

I have a PSU fan as well; Forgot to mention.

^ Yes, PSU does have a fan. I was just mentioning that the PSU fan will function as a form of rear exhaust as well, in addition to the rear exhaust fan.

I have found that 80mm fans are much louder than 120mm that moves more air.

I think thats true

Check my other thread if you want to help me out with recommendations Thanks

Would having two Scythe S-Flex SFF21F fans attached to a Thermalright Ultra-120 eXtreme heatsink be a good thing for my near-future PC? Not to mention the case fans from the Thermaltake Armor +. If they will all work together, great, but all I fear for it is a heat trap.

Like a push pull fan setup? It would bring your temperatures down, but I'm not sure if it's worth the noise an extra fan would produce.

Then again, it's all personal preference when it comes to fan acoustics

Slightly increased noise, or a hot PC? (temperature wise, not sex appeal wise) I know where my heart is at! Depends on the "noise" output of the setup too.

Having push pull on a Thermalright will increase noise but result in cooler CPU temperatures.
Using that kind of configuration would all come down to a few things:

a) Can you afford the extra fans
b) Is the extra noise a problem
and
c) Do you REALLY need the lower temperatures

For most machines, a single fan set up on the heatsink will be perfectly fine.

1. The larger the fan the more airflow and the slower it has to spin to achieve the same amount of airflow as a smaller fan. There are lots of fans that claim to be quiet but imo there is only 2 fans to consider for silence, Nexus for the best silence at the loss of airflow or Noctua for still silent but more airflow.
3: Depends on your case and specs. Some may be fine with a single 120mm exhaust fan and the gamers who have setups that run really hot may want/need a fan in every slot there case has room for.
4: No not all heatsink fans are the same, they are not the same as case fans in lots of cases and generally good for cooling but not for silence.
4a: Nope, some heatsinks are designed to be run totally passive. While some may be aimed at getting the coolest components regardless of noise or other factors. Some are made of copper and some aluminum etc