[Bloodline]

hi i don't realy know much about audio and i wanted to purchase a good pair of headphones for around €150.i listen to all kinds of music but mainly rock and these headphones will also be used for pretty long gaming sessions. i wont take these headphones outside so cheap amp or a DAC is also an option. i prefer over ear headphones. and since i don't plan on taking these outside i don't realy mind if they are open back. so far i was looking into  ATH M50X and senheiser hd 518 or 558

 

[OMGLadyGaga]

HD 558/598 are always a good option. I also really like the Fidelio X1 if you want more bass presence. M50x also a decent choice but if you don't need isolation or portability I think the others are simply better options.

 

[GREQ]

Only problem with the Fidelio X1 is that you can't replace the earpads. 
 
Another idea for you is the Beyerdynamic DT990 Pro.
But the others previously mentioned are also good ideas.

 

[Youth]

DT990 Pro 250 ohm. With amp.