Price: Below $200, but above is OK too. Give a range or something? Or some indication as to what value for money comes with spending more (eg "above 9000 you will see little improvement except in the 200-201hz range, so I recommend only spending 8000" or something)
Location: Next door to m0o (figuratively)
Genre: Dubstep, Jungle, DnB, but also symph, electronica, hip hop
Where will be using: At home, but on the move when I'm going somewhere long (eg on a plane). If they can't be used on the go because they need an amp or something (insert some reason why they cant be portable here), that's fine too.
Connecting to: Computer / iPhone (on occasion)
Using it for: Music, games (Uh, just say 50/50, because I have music always on, some games I mute music so I can listen to mine, but still have sound effects, some games I listen to the game music. Games I play are stuff like Minecraft, Amnesia, Machinarium, so its not like there is a big void between music and games (as I would imagine there would be if I played TF2 with all those gunshots))
Important stuff: Noise cancelling, I live in a very noisey area (Car garage over the road, much reonvation and gardening, lots of power tools/cranes/ also there is a school, so kids going AHAHAHAHHA), active and/or passive. Comfort is a must, I bought some Microsoft headphones one time (lol i know right) and they killed my ears. Right now I have some Plantonics, which are like pillows, sooo gooood. Full size headphones please, them little ones are annoying for gaming (also the whole comfort/noise cancelling thing (although now that I have said that, I am sure you will be very clever and tell me that you can get comfy/noise cancelling inner ears)).
I think a 'good headphone' is: Smooth and happy and big and comfy. The headphones must be happy, that is very important to me.