Okay, I'll play along. A chance at free stuff can't hurt, right?
I see a lot of desire for comfort. This doesn't surprise me in the least. I understand the need for the headphones to just melt away. That's one of things I look for too. But I don't care too much about comfort. Ack, hypocrisy! Nah. I've just found that I can put up with any discomfort if I'm adequately distracted. Even Grados melt away on my ears. Or maybe especially.
What I look for in headphones is a connection to music. Not necessarily realistic, or hyper-detailed or transparent. If I wanted realistic I would blow all my money on speakers, neighbors be damned. If I wanted hyper-detailed I would already be rocking a K701/2 or HD800 on my head. Maybe not the HD800, since I'm poor, but you get the idea. I guess what I'm looking for is something musical, personal, exciting. I want a hole drilled in the floor where my tapping foot sits. I want pencil fragments to litter my desk from overzealous play-drumming. I want the pads on my ears to be soaked with sweat, tears, maybe a little blood if the phones have Grado pads (sorry for stealing your line FraGGler).
Coloration, then. I want a headphone colored to the moon and back. Nah, that's not right. Transparency, accuracy, realism, all of those are still important and play major roles in my enjoyment. So I'll steer clear from Bose, thanks. I want a touch of color, though, not total neutrality. Neutrality can work well, but I doubt I would enjoy it. I'm a fan of using a little extra saturation with my LCD monitors, even if the display is no longer accurate. I like my headphones the same way.
I need punch, too. I so want to try electrostatics, but I don't think I would like them. I want to feel the bass in my ear. Don't read that as me being a bass-head. I love SR60i bass, even if it's a little light. If I can still feel light bass, that's good bass. I want punch everywhere else too, in the midrange and highs. I want to feel the music as much as I hear it. I'm really not into any one specific frequency range, but if I had to choose I would choose the midrange. That's where most instruments rock, and what I think brings the biggest smile to my face when it's done right.
I like detail too. I don't necessarily need to hear the flea crawling across the flutist's forehead, but but I want to hear the growl of an electric guitar, the blare of a horn, with all the resonance that makes it sound right, like its right next to me. I don't want to feel the flutist's flea, but I do want to feel the trumpeter's saliva.
That's one reason why I'd pick headphones over speakers. That's part of the intimacy of headphones that I love. The warmth of two little drivers nestled against my cranium. The knowledge that unless your roommate cuddles up next to you awkwardly, he will not hear what I hear. It's a little show just for me.
But okay, this was supposed to a paragraph or two. I'm rambling. Back to the musicality. I think that's why I became so attached to my current Grados, and will hopefully become more so to my HF-2s. They've got punch, they've got a great forward midrange, they've got what everyone calls PRaT. PRaT's probably the biggest thing I'm looking for, because it gives the music an energy that can't be found short of a live performance. I'm looking forward to a tube amp for their warmth, something else that adds to musicality. I'm not upgrading to seek the flaws of my lossy or poorly mastered files. I'm upgrading to get closer to the music.
So, uh, in summary, PRaT, punch, and warmth?