Need help picking headphones ???

Hi I'm Ash

After a few years of searching I am just about to give up my search for the best sounding headphones. I have bought audio teknika, sonys, beats (poor sound quality), sennheisers and more(all around £100).
So I have decided to up my budget to £200 and here are a few I am looking at:
Beyerdynamic DT250 Headset - 80 OHM,
Sennheiser HD25-1-II BE - Headphones ( ear-cup ),
GermanMaestro GMP 8.35 D Closed Back Monitor Headphones,
GermanMaestro GMP 400 Open Back Headphones,
P5 Mobile Hi-Fi Concert for 1 Headphones - Black(my fav so far),
Sennheiser HD 598 High-End Open Circumaural Headphones

These are the ones I'm looking at. I'm not botherd about looks I'm just looking for good quality sound. So it would be real helpful if anyone could give me some advice ? I am mainly using my iPhone 4/5 and laptop to listen to all types of music.

Also I was thinking of buying the the e17 headphone amp aswell ?

Thankyou

 

There is a lot in there! What is the main use for them and what are your tatses in music?