Airflow, Am I doing it right?

I'm Building a PC using this case http://www.amazon.com/NZXT-Mid-Tower-CA-S340W-W1-Glossy-White/dp/B00NGMIBXC/ 

This is my second time building a PC, the first was around HL2 and from what I can tell is cards have gotten bigger, and cases smaller.... Anyway I am still inexperienced and I'm hoping someone can help point me in the right direction when it comes to airflow. 

I will be placing two intake fans in the front and two exhaust fans in the back, I will also be placing one on top, is it ok to just place fans wherever and have one place for exhaust or do I need it to be pushed out in certain areas? Here is a visual aid of where I will be placing them, sorry for the bad modeling, I just wanted to give an idea as fast as possible, arrows will be pointing where I will place fans. http://imgur.com/u392ZkJ

I would have the front 2 fans intaking.  Then the rear exhausting.  With the top fan either leave it empty for passive cooling or have it as an exhaust as well.  Generally you want front and bottom mounted fans intaking and top and rear exhausting.

If the bottom fans intake wouldn't that build allot more dust inside? Also... what would be the downside of the bottom outtaking and the top intake? 

A lot of the time bottom mounted fans will have dust covers to avoid the majority of dust, all though sadly not all dust gets caught. Really in my opinion bottom mounted fans are not super effective and not worth the hassle. I prefer front and maybe a top intake then rear exhaust. The point is to always have more air going in then out via fans. Air will get out other ways and if there is positive airflow in the case dust won't stick around as easily if it does get in the case. 

Not if you have dust filters, which is why i am personally autistic about cases having dust filters put everywhere by the manufacturers, front intake, bottom intake, and even upper part of the case so dust doesn't accumulate from the top when the PC ain't running, or is silently running.

Due to this i'd rather use the back of the case for passive exhaust due to all the openings that can't be covered by dust filters, but dust settles harder there and the pressure from front intake and bottom intake will just blow all the dust away easily, while using mainly the top as fanned exhaust [which is perfect because the top exhaust forces the bottom and front intake airflow to go into a diagonal right into the back in a sum of pressures].

My ideal case because of this is the Corsair Obsidian 550D, albeit i'd like it if it was a better quality build due to Corsair being bad in that area, but functionally i love it.

 

As far as bottom outtaking and top intake, warm air always accumulates on top because physics, ergo everyone uses top as exhaust by default. But you can try both and see if it makes any difference, maybe a 1 degree or so difference on the GPU where most of the air hits, i don't know.

Thanks for all the good info guys,  also, one more question, GPU cooling, without water cooling, keeping the case cool will be enough? Is there a method of keeping it cool besides a water cooler? 

The old standby is popping off the side and pointing a table fan at it. Of course if you have to do that your case is getting too hot, or your overclock is heating things up too much...

Good fans will make a difference. The more air you can move, the cooler you can keep the inside of your case. As for noise, don't take any of my advice for I have non to offer. Bother of my side panels are off and I watercool. Still use a table fan. Haven't found anything more effective.

The coolermaster sickleflow fans seem decent enough for aircooling, I'd imagine the Corsair air series I use for my rads would work just as well. Sleeve bearing fans don't like facing downward, so that might rule out the CM fans for you. 

Theres only one exhaust fan mounting point on the back of the case, so you want two front intake, one top intake and one back exhaust?

The psu can be exhaust if its flipped upside down, generally not recommended. 

I guess if your only using the top two pcie slots you might be able to shove another fan as exhaust by removing the remaining pcie retaining brackets and supergluing it in place. 

What kind of cpu cooler are you using? there will always be a fan with the cpu, which can change airflow. Mounting an air cooler to blow out the top might be very efficient.

Also, having 3 intakes and one exhaust is a bit overkill for positive pressure. The most important thing is that there is an unbroken current of air flowing through the case, and that the positive pressure is only slightly positive. I've tried super positive pressure and my system was 10 degrees warmer than with a slight positive pressure. 

I like to think of it in terms of how heat naturally wants to flow. The GPU is already trying to push heat either into the case or out the back, so we want to work with the GPU to move as much heat out the back as possible. Front fans should pull in fresh air to the GPU, then the rear fan and GPU fans blow the air out the back. If you have an air cooled CPU then the same logic applies.

If there will be fans on the top then I would set them to blow up and out, as heat naturally rises so you will be able to move any excess heat away from the system fastest and easiest this way. Also this will help to keep dust from settling into the case from the top, as the fans will be blowing the dust away.

Depending on how your PSU is in the system and how the case allows for it to be mounted I would just follow the same basic idea: intake through the bottom and front, exhaust through the top and back.

It's perfectly fine as it is, however, if you want to optimize you fan mounting spot to their full potential then put have 2 front intake fans on med-high setting, an exhaust at the back at a med-high setting, a fan on the bottom (if there is a dust filter for it) on medium and 2 top exhaust fans on a LOW setting. Putting the top ones on high could cause dust to come in through random cracks due to negative air pressure.

Your setup should be fine, but if you don't plan on doing some really high overclocks I don't see why you would need all of those fans. My define r4 (which doesn't have the world best airflow) only has three case fans. two in the front pushing in, and one on the rear for exhaust. With this setup and a good cpu cooler i have achieved some relatively high overclocks on both my cpu and gpu. 

more airflow isn't always necessary. Before i overclocked anything my pc ran fine with just one intake and one exhaust.