Sennheiser 800.
But the headphones are only the last item in a chain of components that must be first rate in order to really evaluate the potential of the headphones. The differences in headphones is highly exacerbated by the electronics you have behind them. Often it is the difficulty in driving different sets them apart. I have top tier, Sennheiser, Focal, Ultrasone, Dennon, Byerdynamic, and several more. It wasn’t until I had really achieved great electronics was I really able to assess the headphones. My ratio of investment in electronic to headphone is about 8 to 1. So, by far the most money is in the electronics. I was shocked at how the difference between the Focal Utopia and Senheisser 800s dissipated as my electronics got better and I was left with Sennheisser being more open and far more comfortable. Hense for the last few hundred hours of listening I only used the Sennheisers although I have a bunch of other top tier headphones.
In the long run, to get the incredible sound headphone system I got.. it was the hundreds of hours (and thousands of dollars) that I put into my electronics that got me there... the headphone search was too soon and made much less of a difference.
You can see my headphone system under my virtual systems.