I'm currently listing my components and got everything figured out except for the CPU because i'm doubting between an i5 4690 (€227), 4590 (€205) and 4460 (€180). Is the performance diffrence between the 3 huge compared with the prices?
Frankly no. The sweet spot would be the 4590, but again, not much difference over the 4460 and you would not be able to tell. Get the 4460 if you're on a budget and you'll be good for a long time.
In the US, the price difference between the 4460 and 4590 is usually like $12 so the 4590 is probably worth it, but I don't think the 4590 is worth €25 more than the 4460. The 4690 is overpriced in every country.