Are noisy fans really that big of a deal?

No not to me anyways, my PC can get quite loud under load and with my headphones on I never even notice it.

Even "noisy" fans these days generally aren't really that loud. Especially since you are using headphones, I wouldn't worry about new fans / cooler.

with headphones, not so much. but if you have other people in the room, it may be annoying. also, it depends on how noisy it is, most of the time it is ok unless you have lots of really noisy fans

I don't think so because you use headphones and apparently noise isn't in your consideration.

Cheers!

It's a subjective thing. Your system fans or your gpu fans is most likely to be louder unless you using the stock cpu cooler provide with your cpu. If you are alone with your pc in a room and you use headphones, you can block some of the noise of your fans. If someone else is in the room, they may not like your whirring fan noise then.
I have a noise cancelling headphone so it helps to nullify that noise when i need the fans at full speed.

It's subjective so I'm not sure what to tell you.

Also, usually the GRAPHICS CARD is the biggest noise source in a gaming PC.

If you want to build a nearly SILENT PC it's not that hard.

A lot of people can make their PC's quieter by simply adjusting the CPU fan (and motherboard fans if possible) using the motherboard fan software.

Summary:
I can't give more advice. If you want specific advice that's a different story but it depends on what setup you have and what you feel is a "noisy" system.

It's a matter of preference.

Quiet PCs are useful to those who have surround sound audio, as the drone of a fan would be noticeable over the speakers and get annoying. Also for those who record audio, where outside noise needs to be filtered out or cancelled, and too much will degrade the quality of the audio.

Those who use headphones might have a higher threshold where noise becomes an issue, either from hearing it over the headphones, or the sound overpowering the noise-cancellation of a mic used for team chat or the like.

well since you're using headphones while gaming you won't even notice the noise no matter how loud your PC is. "Loud" is also subjective, some people don't mind fans running at 1500rpm+ which is decent for me, some want pure quietness, so fans running at like 800rpm are for them or to even make it less noisier using no fans and only utilising them when the PC gets to a certain temperature. So it'll all depend on your liking. But if you do opt to purchase quiet fans, i suggest you do your research and read reviews like of newegg and amazon. Plus if you're mobo can control fan speeds you can adjust it to your liking, just make sure you pick the right fans which can be supported/controlled by your mobo configurations.

good luck with your build!

So this doesn't apply to you.

But it's very simple, just use what you got, if it starts to bother you down the road, can always replace it then, don't have to get all your components all at once or on one seating.

generally all fans will remain at a level that you eventually tune out as you use the computer. the only time this was not true for me was with a dell r900 that sounded like a jet engine taking off.

Any 1U and a lot of 2U servers are going to always be too loud for anyone with functioning ears to ever call them quiet, IMO.

its a 4u. and i definitely wasn't expecting it to be quiet but i can hear it when its in my basement.

'Cuz thin boxes forces you to use small fans with high RPM to compensate for the small CFM. I if was forced into this situation I would investigate slowing the fans but put like 10 of them to compensate. OR seeing how they did it to the super-thin Macbook Airs, use them thin radial(?) fans.

As some said, it's somewhat subjective. I went for hydrodynamic or magnetic fans for the much lower noise. ball bearing fans have a pretty loud buzz (according to the speed), that many people don't like. It also matters on your case, and how much noise it suppresses.

Lots of people want quiet or even silent PC's regardless of what configuration they have. All my fans are almost silent except my video card which is still pretty quiet but even in idle I notice it at times so my next card will be one that has 0dB fan mode.

(I don't understand your comment about quiet PC's being useful to surround sound users...)

*OTHER:
I never did comment on a cooler model as I said it was subjective, though I will recommend a particular cooler and that is the Noctua NH-U12S. You should also open the FAN SOFTWARE and adjust that for optimal noise/cooling (most motherboards have fan software such as "Asus Thermal Rader etc" from the motherboard support site though it may be BUNDLED in a main package... see the motherboard manual. Not all case fans can be controlled from the motherboard (some are 3-speed controlled via a switch). Some are non-variable.

The Cooler master 212 Hyper EVO cooler is cheaper and quite adequate for most people, though it is louder especially under CPU LOAD. Many people are fine with it, others will spend extra on the quieter coolers. At roughly $30 difference that's 3% the cost of a $1000 PC so it's not bad if you think about it that way.

On my dad's PC I set the Noctua NH-U12S fan speed to 300RPM (20%) and started the ramp up at 45degC. The CASE fan started to vibrate the whole case so it's temporarily disabled while I sort that out which probably will be some thin material I can shove between fan and case to dampen vibration.

I replaced my case fans with variable PWM fans and while I did set a profile they never go above 800RPM and are essentially SILENT.

Other:
As someone else said, you can replace components later. In the case of the EVO cooler it's possible to replace the fan as any compatible 12cm fan will work though not all have the right specification (i.e. PWM, RPM range).

*Note that fan software uses 40% as the minimum for case fans (20% for CPU) usually. You want the maximum minimum to be about 700RPM or roughly 1800RPM max. By variable it has a range such as 700RPM to 1800RPM but NOT listed as 1800RPM plus/minus 10%.

As said, my dad's PC (Intel i5-4670K) can stay cool enough, at 20degC room ambient to have the Noctua fan spin at only 300RPM which is silent. I replaced the EVO cooler fan with a Noctua and it also become silent in idle.

There are GRAPHICS CARDS (if you haven't bought yet) that have a 0dB option so the fans will turn off. Some but not all of the NVidia 900 series have this (960, 970 etc..).

So the CPU fan and CASE fans are really the only thing that is easily replaced (or rather, cheaply replaced).