TEHDARKSIDE

Already have a Phanteks Enthoo pro, which I'm quite happy with tbh, so really no point in upgrading the case . I'm going to be buying a supernova g3 as well,  already taken that into account for the overall build price. 

Standard 60hrz, If I do upgrade it would most likely be 144hz. I care more about smoother gameplay than the quality of graphics. 

Get the S7 if you want Physical features, such as waterproofing. Also, if you do a lot of physical store shopping, Samsung pay is awesome. Not sure if you have heard of it, but you can literally swipe your phone wherever it is physically possible. Not sure when it is coming out in the UK, but if this phone is meant to last a while and it is worth it, then I would look into the s7, my brother has the s6 (which has samsung pay) and that is one of his main reasons he loves it. If you also want the best phone camera you can buy, then get the s7. Like @Aytex said, you could probably get cyanogen mod on the s7, which basically makes it stock android + some extra stuff.
 
The Nexus 6p is also a great option. It does everything great. While it is not on-par with the s7 on many aspects, it is usually close behind and is an all-around fantastic phone. if you want stock android with no hassle, then get this phone. The camera is great, battery life is still great (It can last me the whole day of constant gaming, web surfing and texting use with around 15% left). And the fingerprint reader is awesome. You will never use the lock button again, except to turn it off. Its fast and in a very ergonomic place on the back. 
 
Both phones are great options and you won't be disappointed with either of them. They have thier own features and they all are worth it. I love my Nexus 6p and I don't have any major complaints. While my brother has the s6, they are very similar, and he loves his. So get whatever features you would appreciate the most.

I... What??? OP already said that they looked at the M50X... Not to mention that your suggestion isn't helpful at all, because Audio Technica currently produces at least 30 different models of headphone...
I think you meant College...
 
Anyway, You could always get something from Koss. They tend to make good headphones for the price, and their no questions asked warranty is awesome if anything ever breaks.
 
The DT770 is quite good, with the Custom One Pro being less so, and the lack of removable cables could be an issue later on (That being said, you can put a mini XLR on most Beyer models, as far as I'm aware.)

Thank you :3