For me the point of this hobby is A/B testing. I personally like the sound of Sennheiser and if I needed to pick just one set it would be one from the 6 series (600,650,660). If you just need a good set of headphones it is a good set to stop if you like it. But if you are in it for the sound you will probably be curious to listen to a few other sets also to compare what they sound like (to you). After having compared a bit you could end up to 1-2 pairs and for me for sure HD6xx are fine to end up with.
For me the point of this hobby is A/B testing. I personally like the sound of Sennheiser and if I needed to pick just one set it would be one from the 6 series (600,650,660). If you just need a good set of headphones it is a good set to stop if you like it. But if you are in it for the sound you will probably be curious to listen to a few other sets also to compare what they sound like (to you). After having compared a bit you could end up to 1-2 pairs and for me for sure HD6xx are fine to end up with.