Depends on what you're planning on using the PC for. If you don't need the absolute top-of-the-line CPU, then no, don't spend the extra 80 euros to buy it; save it for other parts. If you need the extra performance, then spend the money for it.
Personally, though, I don't see either Intel chip "blowing" the FX away. While that i7 is shown having superior single-core benchmarks, it's even on the multi-core benchmarks. And based on the average performance, if the FX 9590 costs 200 euros, then the i7 should cost about 235 euros, not 280. And if anything, the price comparison is even worse compared to the FX-8320 (non-OC'd): the i7's benchmarks average out to be about 47% higher, but its relative cost is ower twice as high (280 euros vs. 125 euros). Sorry, but if I'm going to pay twice the cost, I expect twice the average performance.
Note that I'm not even considering the fact that the Intel chips come with built-in graphics. Sorry, but the majority of people that want/need the level of CPU performance that an i7 brings also want/need a level of graphics performance that Intel HD 4600 graphics cant provide. Which means that the money you can potentially save with an AMD processor can go towards a better GPU, as an i7 with a "budget" discrete GPU isn't going to provide the performance boost over an FX with a mid-/top-range GPU.