Gaming PC Build 1500€ (2200$)

PCPartPicker part list: http://pcpartpicker.com/p/3elIR
Price breakdown by merchant: http://pcpartpicker.com/p/3elIR/by_merchant/
Benchmarks: http://pcpartpicker.com/p/3elIR/benchmarks/

CPU: Intel Core i7-4770K 3.5GHz Quad-Core Processor ($309.99 @ Newegg)
CPU Cooler: Cooler Master Hyper 212 Plus 76.8 CFM Sleeve Bearing CPU Cooler ($29.99 @ Newegg)
Thermal Compound: Arctic Cooling MX4 4g Thermal Paste ($9.99 @ Newegg)
Motherboard: Gigabyte G1.Sniper Z87 ATX LGA1150 Motherboard ($167.99 @ Amazon)
Memory: G.Skill Sniper Gaming Series 16GB (2 x 8GB) DDR3-1600 Memory ($154.99 @ Newegg)
Storage: Samsung 840 EVO 120GB 2.5" Solid State Disk ($83.99 @ Amazon)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($59.99 @ Newegg)
Video Card: Asus GeForce GTX 780 Ti 3GB Video Card ($687.27 @ Amazon)
Case: Cooler Master HAF 912 ATX Mid Tower Case ($49.99 @ Micro Center)
Power Supply: EVGA SuperNOVA 750W 80+ Gold Certified Fully-Modular ATX Power Supply ($103.95 @ Amazon)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($15.98 @ OutletPC)
Operating System: Microsoft Windows 7 Ultimate SP1 (OEM) (64-bit) ($174.23 @ OutletPC)
Monitor: Asus VX238H-W 23.0" Monitor ($157.58 @ Newegg)
Case Fan: Xigmatek CLF-F1455 60.5 CFM 140mm Fan ($25.99 @ Newegg)
Keyboard: SteelSeries APEX Wired Gaming Keyboard ($84.99 @ Newegg)
Mouse: SteelSeries Rival Wired Optical Mouse ($54.98 @ Newegg)
Headphones: SteelSeries Siberia v2 Headset ($89.99 @ Best Buy)
Total: $2261.88
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-22 11:56 EDT-0400)

This is my suggestion. Sorry for GBP £. I have no idea bout German Vendors but Amazon are pretty consistent.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor (£161.99 @ Aria PC)
CPU Cooler: Corsair H55 57.0 CFM Liquid CPU Cooler (£49.18 @ Amazon UK)
Motherboard: MSI Z87-G45 Gaming ATX LGA1150 Motherboard (£103.84 @ Ebuyer)
Memory: Crucial Ballistix Elite 8GB (1 x 8GB) DDR3-1866 Memory (£62.99 @ Amazon UK)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Disk (£129.60 @ Amazon UK)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£42.99 @ Amazon UK)
Video Card: Gigabyte GeForce GTX 780 3GB Video Card (£399.30 @ Amazon UK)
Case: Fractal Design Arc Midi R2 (Black) ATX Mid Tower Case (£69.65 @ Dabs)
Power Supply: XFX ProSeries 750W 80+ Gold Certified Fully-Modular ATX Power Supply (£99.42 @ Aria PC)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (£69.96 @ CCL Computers)
Monitor: Asus MX239H 23.0" Monitor (£199.00 @ Amazon UK)
Total: £1387.92
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-22 16:02 GMT+0000)

Left you another ~100Euro to get OS, sorry didn't find 64bit win7 in PCPartPicker!

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor (€197.90 @ Caseking)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (€33.40 @ Amazon Deutschland)
Motherboard: MSI Z87-G45 Gaming ATX LGA1150 Motherboard (€119.99 @ Pixmania DE)
Memory: G.Skill Ares Series 8GB (2 x 4GB) DDR3-1600 Memory (€70.85 @ Amazon Deutschland)
Storage: Crucial M500 120GB 2.5" Solid State Disk (€56.70 @ Amazon Deutschland)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (€47.55 @ Pixmania DE)
Video Card: MSI GeForce GTX 780 3GB Video Card (€499.00 @ Amazon Deutschland)
Case: Cooler Master HAF 912 Plus ATX Mid Tower Case (€74.00 @ Pixmania DE)
Power Supply: XFX 650W 80+ Bronze Certified Semi-Modular ATX Power Supply (€84.69 @ Hardwareversand)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer (€13.40 @ Amazon Deutschland)
Monitor: Asus PB238Q 23.0" Monitor (€209.00 @ Amazon Deutschland)
Total: €1406.48
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-22 17:03 CET+0100)

look this over:

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor (€197.90 @ Caseking)
CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler (€97.98 @ Hardwareversand)
Motherboard: MSI Z87-GD65 Gaming ATX LGA1150 Motherboard (€157.55 @ Amazon Deutschland)
Memory: Corsair Vengeance Pro 16GB (2 x 8GB) DDR3-1866 Memory (€156.93 @ Amazon Deutschland)
Storage: Crucial M500 240GB 2.5" Solid State Disk (€95.95 @ Amazon Deutschland)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (€47.55 @ Pixmania DE)
Video Card: Asus GeForce GTX 770 2GB Video Card (€297.99 @ Amazon Deutschland)
Case: Corsair 500R Black ATX Mid Tower Case (€99.90 @ Caseking)
Power Supply: EVGA SuperNOVA 650W 80+ Gold Certified Fully-Modular ATX Power Supply (€85.11 @ Amazon Deutschland)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer (€13.40 @ Amazon Deutschland)
Total: €1250.26
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-22 17:07 CET+0100)

left you 250 to spend on OS and 1080p monitor

CPU
i5-4670K ( you should overclock )
http://www.amazon.de/Intel-4670K-Prozessor-Sockel-LGA1150/dp/B00CO8TBOW/ref=sr_1_1?ie=UTF8&qid=1395503792&sr=8-1&keywords=i5-4670k
<EUR 219.00>

Motherboard
Asrock Z87 Extreme 4
http://www.amazon.de/Z87M-EXTREME4-Mainboard-micro-ATX-Speicher/dp/B00D5QCLTO/ref=sr_1_3?ie=UTF8&qid=1395503860&sr=8-3&keywords=z87+motherboard

< EUR 105.81 >

GPU
GTX 780
http://www.amazon.de/MSI-N780-TF-3GD5-OC/dp/B00DRR44FK/ref=sr_1_1?ie=UTF8&qid=1395503987&sr=8-1&keywords=gtx+780
< EUR 429.00 >

RAM
G.Skill Ripjaws X 2x4GB ( 8Gb is all you would ever need for gaming )
http://www.amazon.de/G-Skill-Ripjaws-Arbeitsspeicher-240-polig-DDR3-RAM/dp/B004I763AW/ref=sr_1_1?ie=UTF8&qid=1395504038&sr=8-1&keywords=RAM
< EUR 72,30 >

PSU
Seasonic M12II 620 watts
http://www.amazon.de/Seasonic-SS-620GM2-M12II-620-Netzteil/dp/B00HHH8AA6/ref=sr_1_2?ie=UTF8&qid=1395504202&sr=8-2&keywords=seasonic+m12II
< EUR 81.87 >

HDD
WD Black 750GB
http://www.amazon.de/Western-Digital-WD7500BPKT-interne-Festplatte/dp/B004I9J5OG/ref=sr_1_2?s=computers&ie=UTF8&qid=1395504322&sr=1-2&keywords=western+digital+caviar+black
< EUR 65,54 >

SSD
Samsung 840 Evo 120GB
http://www.amazon.de/Samsung-MZ-7TE120BW-interne-SSD-Festplatte-silber-metallic/dp/B00E391KA8/ref=sr_1_2?s=computers&ie=UTF8&qid=1395504372&sr=1-2&keywords=samsung+840+evo
< EUR 68,90 >

monitor
Asus VN247H 23" 1920 x 1080
http://www.amazon.de/Asus-VN247H-LED-Monitor-DVI-D-Reaktionszeit/dp/B00A4415KG/ref=sr_1_1?s=computers&ie=UTF8&qid=1395504498&sr=1-1&keywords=asus+HD+monitor
< EUR 173,90 >

___________________

choose the case, OS , and peripherals by yourself. And sorry, couldn't calculate total. Don't forget shipping fee

PCPartPicker part list: http://pcpartpicker.com/p/3em9Y
Price breakdown by merchant: http://pcpartpicker.com/p/3em9Y/by_merchant/
Benchmarks: http://pcpartpicker.com/p/3em9Y/benchmarks/

CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor ($229.99 @ NCIX US)
CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler ($98.99 @ Best Buy)
Motherboard: Asus Maximus VI Hero ATX LGA1150 Motherboard ($198.98 @ OutletPC)
Memory: G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1866 Memory ($131.75 @ Newegg)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Disk ($139.99 @ Best Buy)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($59.23 @ OutletPC)
Video Card: Asus GeForce GTX 780 3GB Video Card ($499.99 @ Amazon)
Case: Fractal Design Define R4 w/Window (Black Pearl) ATX Mid Tower Case ($99.99 @ Micro Center)
Power Supply: Corsair Professional 750W 80+ Gold Certified Semi-Modular ATX Power Supply ($129.99 @ Micro Center)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($19.98 @ OutletPC)
Operating System: Microsoft Windows 8 (OEM) (64-bit) ($97.98 @ OutletPC)
Monitor: Asus VS238H-P 23.0" Monitor ($134.99 @ NCIX US)
Monitor: Asus VS238H-P 23.0" Monitor ($134.99 @ NCIX US)
Keyboard: Corsair Vengeance K70 Wired Gaming Keyboard ($129.99 @ Amazon)
Mouse: Logitech G400s Wired Optical Mouse ($44.99 @ NCIX US)
Headphones: Corsair Vengeance 1500 v2 7.1 Channel Headset ($69.99 @ Newegg)
Speakers: Logitech X-140 4W 2ch Speakers ($26.09 @ B&H)
Total: $2247.90
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-03-22 12:11 EDT-0400)

i5: i7's are completely useless for gaming, you'll get maybe 1-2 fps more with one. They really are only useful if you are rendering/editing/recording stuff.
H100i: It has great reviews and will pretty much allow you to take your overclocking to the limit.
Samsung 250GB SSD: This will allow you to put your OS and most (if not all) of your games on it.
Dual monitors: This setup is awesome for social gaming. I always have skype or spotify open in one, and the game in the other. This is also great for produtivity.

here you go,it is a bit expensive but you can customize it as you like. - http://pcpartpicker.com/p/3emme

32gb of RAM? Why...

@zeph_yr
more ram couldn't hurt,i know that it will increase the price but it would futureproof the pc more.

No game will use 32gb for at least 20 years... By then everything else in the computer will be old anyway. Even 16gb is overkill for gaming, but the OP insisted on it. I think a GTX 780 will be better than 32gb of ram.

The price will only go up if there aren't similar stores/deals to MicroCenter in Berlin.

the gtx 770 could use the extra ram.

People, Please Stop!!! OP wants PC in Germany Please read what he wrote! Prices for your part lists will be about 1.5 or even 2 times higher. Its something like 1 Euro=1 Dollar!

Graphics cards do not use and are not related to RAM. They use their own ram (usually GDDR5).

It will probably be the year 2020 by the time 32GB RAM is needed.