Even though I listen to quite a bit of heavy-ish stuff (Godflesh, The Jesus Lizard, Shellac, Christbait, early Pitch Shifter, Budd, Corrosion of Conformity) - I don't really use my headphones for this kind of listening. I currently have the Sony 7506s and the Koss KSC-50s. 100% of my listening through these is electronic/ambient and I give the thumbs up for the Koss and the Sony for this purpose. The main reason for this is that I use my headphones at work, and anything other than minimal electronica I find too distracting. Guitar music gets put through the speakers when I am at home so I can jump around, vaccuum etc etc
Now...getting to the point of all this. When I was auditioning, I used a variety of music styles and vividly remember that the Grado SR60s really impressed me for guitar-based music. Don't get me wrong, the 7506s have sounded mighty fine with this style of music the few times I have used them for this purpose, but the Grados really had something special going on that made the guitars come alive in the short time that I had to audition. Can't recall using Godflesh, but the Jesus Lizard sounded better than I have ever heard them sound. You should have seen the smile on my face!
I must add that the SR60s were pretty competent with electronic music, but came a bit short with the Mick Harris bass etc - the Sonys edged them out here I felt.
I think if you already have something that is working well for your DVOA and stuff like that, and you want a headphone to use with metal/guitars, have a close look at the SR60 or even the SR80. They are certainly in your price bracket. If you want a more versatile headphone, the Sony 7506s/V6s won't disappoint. The Beyer DT250s sound like a good buy also, but are more pricey I think.
Good luck!
