** Edit ** (note I posted this before seeing the reply from Iachigo above about budget in Euros **
You're going to need to make some degree of compromise.
We can make you a (relatively) quiet PC with excellent performance on current games.
We can make make you a PC with excellent performance on new games in 4 years with no upgrades...
But we can't make you a quiet PC with excellent performance on new games in 4 years with no upgrades.
The pace of change on video game graphics is simply too fast. In four years there will be games available with so much power that only today's very highest graphics card will be able to handle it well. And that would no longer be quiet.
So we will need you to answer a few more questions.
1) Is the budget 1000-2500 US Dollars, or Euros?
2) When you speak of using this PC for four years, do you still want excellent graphics performance in 4 years? Or is it OK if this PC requires lower settings for the games that come out 4 years from now?
3) If you want to have excellent graphics in 4 years, would you be willing to consider a water cooling system? It would require a more complicated initial setup, so some people don't like the idea.
Here is my first attempt at this.
I would call this a relatively quiet system with excellent graphics TODAY. In four years this system would definitely need to use lower settings to play new games.
All of my selections were influenced by balancing reviews from this site, www.silentpcreview.com, and www.jonnyguru.com.
I'm listing links to prices on NewEgg.com, but I'm sure you will want to purchase from somewhere in Europe to avoid shipping difficulty and delays. I don't speak French well enough to navigate any of those sites.
So I will not post any specific discounts or combination deals available through NewEgg.
CPU
Intel Core i5-2500K Sandy Bridge 3.3GHz (3.7GHz Turbo Boost) 4 x 256KB L2 Cache 6MB L3 Cache LGA 1155 95W Quad-Core Desktop Processor BX80623I52500K[/i]
$230
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115072
Motherboard
ASUS P8P67
~$170 (not sure of source so rough price estimate)
RAM
(you had a 3x2GB RAM kit in your initial list. The LGA1155 motherboards have dual channel ram. That 3x2 kit would be for a LGA1366 motherboard)
G.SKILL Ripjaws X Series 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL7Q-16GBXH
$340
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231446
Normally would never recommend that much RAM to start. Half of that would be more than enough normally, but with the no upgrade policy this seems like an easy safeguard against future load, without added noise.
Drive 1 (for OS and your main game... other programs and file storage will be on Drive 2. Make sure you move the Windows document folder location to your storage drive)
(This is the first of the next wave of solid state drives to become available on NewEgg. If you can wait a few weeks, at least two competitors will emerge w/ the the new SandForce SF-2200 controller and better (in some reviews) performance at lower price. Option A would be 'OCZ Vertex 3' expected to cost ~$300 for 120GB.)
Intel 510 Series (Elm Crest) SSDSC2MH120A2K5 2.5" 120GB SATA III MLC Internal Solid State Drive (SSD)
$314
http://www.newegg.com/Product/Product.aspx?Item=N82E16820167042
Drive 2 for storage and lower priority stuff
SAMSUNG Spinpoint F3 HD502HJ 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
$50
http://www.newegg.com/Product/Product.aspx?Item=N82E16822152181
A 500GB hard drive has fewer platters -> less mass -> less vibration so it is more quiet than a 1TB drive. No home user really has more than 500GB of data that they need instant access to. If you run out of space on this then get an external drive that you can connect, move things onto, and then shut down. This will help your noise and heat.
Also http://www.silentpcreview.com/ has some good tips for ways to mount the hard drive so that vibration is not carried to your case.
Video Card
I would recommend a GTX 560 Ti as your graphics card. It is faster than the GTX 470 that you listed, but it's also less heat and noise due to a more efficient processor.
I'm not particular to any of them, but I will use this one as a place-holder.
MSI N560GTX-TI Twin Frozr II/OC GeForce GTX 560 Ti (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
$250
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127565
That is the only component in this build that might be bad in terms of noise, but it's the best we can do with the amount of performance required.
If it is too loud then it is not the graphics card's fault, it's the cooler fans on the card. If that happens, then get this and replace the cooler. This one is a better cooler, but I don't know of any GTX 560 Ti's that come with it.
Acrtic Cooling Accelero XTREME Plus VGA cooler + VR005 accessory kit
$83
http://www.arctic.ac/en/p/cooling/vga/18/accelero-xtreme-plus.html
Case
Antec P183 V3 Black Aluminum / Steel / Plastic ATX Mid Tower Computer Case
$139
http://www.newegg.com/Product/Product.aspx?Item=N82E16811129174
Power Supply
(If you find that your power supply is the one thing you hear in your case, one of these may be more quiet)
Option A:
Antec CP-850 850W Continuous Power CPX SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC "compatible with Core i7" Power Supply
$120
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371024
(note: The 'CP' series power supplies are a unique 'CPX' size/shape that is slightly larger than standard ATX power supplies. This design allows for better component spacing and quieter cooling, but at this point there are only 4 four cases that can fit this supply... Antec's P183, P193, Twelve-Hundred, and DF-85)
Option B: if you do not choose any of the Antec cases that accept the CP supply
ENERMAX MODU82+ EMD625AWT_II 625W ATX12V v2.3 / EPS12V CrossFire Certified 80 PLUS BRONZE Certified Modular Active PFC Power Supply
$145
http://www.newegg.com/Product/Product.aspx?Item=N82E16817194067
CPU heatsink cooler
Noctua NH-C12P SE14 140mm SSO CPU Cooler
$75
http://www.newegg.com/Product/Product.aspx?Item=N82E16835608019
http://www.noctua.at/main.php?show=productview&setlng=fr&products_id=35
Operating System You already have it
Optical Drive 1
LG Black 10X BD-ROM 16X DVD-ROM SATA Internal Blu-ray Disc Combo Model UH10LS20 LightScribe Support - OEM
(plays blue ray, read/write DVD's)
$68
http://www.newegg.com/Product/Product.aspx?Item=N82E16827136183
Total $1497, without optional graphics cooler or monitor.