AKG Q701's were on sale a while back for £95-£120 depending on if you get hit with customs or not (I posted the deal in sound city), normally sell in the UK for £220-£300 with a RRP of £399.
These are basically in the top 5-10 gaming headphones on the planet and those that are better cost considerably more for very little improvement. Basically these are "end game" in terms of sound especially in competitive fps.
Unfortunately the mixamp isn't powerful enough to drive them sufficiently whilst using voice chat so I will need to buy a Schiit Vali and double amp them.
My new rig will be:
Wireless 5.8 Mixamp (RRP £120, I paid £75 but I had to buy a battery, few additional wires etc pushing it up to £100) + Q701 (RRP £399, I paid £120) + Schiit Vali (£110 ish new) + DX clip on mic (£1.58)
If you were to buy my new rig today brand new online from the UK it would cost you £400-£500
The difference being my rig will last me a lifetime (most gaming headsets last a few years if your lucky).
Ryan a guy on here who has listened too and owned many headphones including ones which cost £30K-£100K reviewed a gaming headset which ocuk will be stocking for £60-£70 the other day and rated it very highly for the money. Read his review in his thread in sound city.
If you are interested in sound quality, please visit the sound city section of the forums and the guys there will recommend you the best headphones for your budget.
I own AKG Q701, Sennheiser HD600, HD558, HD25-1 II, Phillips Fidelio X1 and a few IEM's and owned a few other headphones in the past like the HD 595 and HTF600's.
I sold the HTF600's on the mm for £22.50 delivered in brand new condition fully boxed (had only owned them for like a month from new) and the guy I sold them to was ashamed to admit they sounded better than his £200 Beats by Dre's.
Basically you don't need to spend a lot like myself you just need to spend wisely, make the wrong choice and you can end up with a crap set for £200, make the right choice and you can end up with a superb set for £30. Their are amazing gaming headphones out there for every budget, the only issue with the PS4 is that you really do need a mixamp which costs like £120 and it's wired.
If you want to go wireless then cheap choice would be sony and the expensive choice being A40's but they will never sound as good as a wired setup for the same money.