Depends on what you need them for.

I know only studio use so keep that in mind.

Sennheiser HD600, HD650 - people that buy these often improve their mixes or the balance, if their rooms and other headphones are bad.

Audeze LCD 2 or better LCD X - these are super nice to listen to, maybe a bit "things sound better than in reality". Mastering guys use the LCD X a lot, saying the bass is very accurate, just that there is dip in the midrange around 3khz, that needs to be corrected with software.

Sony MDR7520 - no longer available, EU has banned these for being able to be super loud. These are closed back headphones that "don't make things nicer and make you work on your mix/master". The lower models MDR7510, MDR7506 are different, I never had an opportunity to try them.

Focal, Neumann, Austrian Audio, Audiotechnica, Beyerdynamic make some nice studio headphones. It's all very personal. I like my sonys a lot, but my friend can't stand them liking his LCD X much much more...