Yeah, there are some things to change.
If you will not be overclocking then the processor is fine. However, the 4690K is recommended if you are willing to overclock as it will have a longer useful life than the non-overclocking 4590 processor, although it will cost more. I will assume you do not want to overclock.
You chose a small compact motherboard (mATX size) and a normal mid size case. Although the smaller motherboard will fit in the larger case, I think it's best to match up the size, no reason to go with a smaller motherboard unless you absolutely needed to save money because it was cheaper or something. If you prefer a more compact computer, it would be possible to choose a smaller case and motherboard. I will choose a smaller case.
I wouldn't recommend WD Green to store the OS. It's best used as a secondary drive for storage, not for the OS. Even then, there are apparently issues with head parking (power saving feature that apparently causes a lot of issues because of how short a time and aggressive Western Digital has set it to work for). I found a cheaper faster 7200RPM Toshiba hard drive instead.
Optical drives are generally no longer needed unless you have a specific need for them.
From what I can find, Fractal power supplies are fine, but 500 watts is a little on the low side for an R9 280. I chose a decent EVGA 600B power supply instead for just 1 Euro more, 600 watts is a little more comfortable to have.
With the money saved, I was able to pick a R9 280X which will offer improved performance.
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i5-4590 3.3GHz Quad-Core Processor (184.90 @ Caseking)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (32.99 @ Amazon Deutschland)
Motherboard: ASRock H97M Anniversary Micro ATX LGA1150 Motherboard (75.89 @ Amazon Deutschland)
Memory: Kingston Fury Black Series 8GB (1 x 8GB) DDR3-1866 Memory (69.00 @ Amazon Deutschland)
Storage: Toshiba 2TB 3.5" 7200RPM Internal Hard Drive (74.90 @ Caseking)
Video Card: XFX Radeon R9 280X 3GB Black Edition Double Dissipation Video Card (229.90 @ Caseking)
Case: Cooler Master N200 MicroATX Mid Tower Case (37.50 @ Amazon Deutschland)
Power Supply: EVGA 600B 600W 80+ Bronze Certified ATX Power Supply (62.12 @ Amazon Deutschland)
Total: 767.20
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-02-10 19:16 CET+0100
The cost comes in at just under 770 Euros.