I've never spent that high (only in the £50 range, which until recently was fine by me*), and my recommendation at this point is "Don't bother". Two reasons;
1: You'll spoil your ears. The better you go, the pickier they get, and the reason this is a problem is explained in point 2...
2: Everyone seems to cheap out to some degree. When (and nowadays, it's almost always "when" not "if", with few exceptions) they break, you're on an expensive treadmill for more of the things.
*When my super-gently-used only-two-years-old over-ear Sennheisers snuffed it while I was on holiday earlier in the year, I had to grab a cheap pair of Tesco Hudl earbuds. Not only was the sound astonishingly good, they were a tenth of the price of the Sennheisers. Lost customer, there, and one who now sees little point in spending huge amounts on items designed not to last very long.