I have recently acquired both a Sennheiser HD600 and a Grado SR325is. For the time being, I am likely going to have to figure out which one I want to keep and sell the other, which is going to be a challenge. I listen to about 90% rock/metal, although most of it is not "hardcore," for lack of a better word. I listen to a lot of classic rock, for instance. What I have found is that faster, more electric guitar-oriented rock can sound better on the Grado, while bands like Fleetwood Mac sound better (to me) on the HD600.
What I am wondering is this: is there a headphone (any price) that really captures the best of both headphones? Specifically, I like the comfort, soundstage, overall balanced sound, lack of sibilance, and forgiving nature of the HD600. Meanwhile, I like the crunch of guitars, snap of drums, speed, and detail of the SR325is. I have seen many posts of this site saying that nothing sounds like a Grado. Perhaps higher-end Grados are what I'm looking for? Any thoughts/opinions are appreciated.