i live in brighton at the moment.
I currently use grado sr-125's for music listening, and really like the kind of sond they have. I love the detail they provide and i enjoy the impetus of it. I expect that i would get this to a higher level, with increased and tighter bass with the higher end models like the rs-1 / ms-pro.
My sennheiser HD600's i do find to be the opposite kind of headphone to the grados. to be honest i don't think i have ever experienced them the way they should be, as i have never had a headphone amp to drive them properly. I have always used my headphones through my PC (i have an x-fi fatal1ty soundcard as i game seriously at quake4....or did before it died, we were the best q4ctf team in europe hah!) I use my HD600s for gaming and movies on my pc, because of the larger soundstage and comfort, which is definitely more suitable for positioning in FPS games.
Obviously, my purchasing of headphones is purely based around music though, as i love my music.
When i demoed the sr125's at the shop before i bought them, i thought they were excellent immediately, i got so much enjoyment hearing the way they were with detail in general, and especially on guitars on prog rock tracks, and funk tracks. That was listening just plugged into an actual linn cd player, which had a headphone out on the player, not even via a headphone amp. My pc soundcard has never done my headphones justice, as i could tell they didn't as good on my pc as when in the shop, so i know i am missing out. So when i finally get a headphone amp, and the hi fi set up i will be buying, i know i am in for a treat.