I think I get were you are going with this.
I'm by no means a pro, but I do some small engineering work from time to time. I've also had the luxury to listen to a wide range of closed headphones as well as audiophile systems.
I've come to the conclusion that you could have two headsets. One for tracking, ENG, monitoring and another for musical enjoyment and composition.
Many studio monitoring headphones can be fatiguing (MDR-7506 for example) but they have their uses.
I used to have an HD-555, and I wish I kept it for its enjoyment/comfort factor. It was by no way a neutral headphone. Ideally, you'd have an HD-800 along with an amp. Of course, thats $$$. I have heard of studios using the HD-650/600/580 series. Although more veiled than the 555/595, they are more dynamic. these seem like the natural choice. I don't think you could go wrong with the K701/702 either. All are great headphones.
Sounds like you have a great setup. I don't even have studio monitors anymore (moved to a condo). For now, my primary cans are the SRH840. I would recommend them if you are looking for a premium studio monitor. They are also very enjoyable and I will be using them at work like I used my HD555s. Everything I liked about my HD25 and HD555, the Shure has it... its quite the can considering its price.