I was in the same boat when I moved my major listening spot to our room with the TV (so I could actually FLAUNT the ignoring of my family members, sequestered under my headphones in their sight, rather than in a separate room as before).
So with all my Grados, I still needed a closed pair of headphones for times when someone else was watching TV.
I considered the Beyerdynamic T 5 p and the Fostex TH-900. My research, since confirmed by actual listening, was that the Fostex had better sound but poorer noise isolation, while the Beyers had better isolation but poorer (though still great) sound. Listening tests added the observation that the Beyers were more neutral yet more Grado-like, with greater transparency, than the more colored, brassier Fostex.
I bought the Beyerdynamic T 5 p. I figured that if I were ascending into the stratosphere of critical listening, it would not be in a noisy room with closed headphones, but rather in a quiet room with Grados or Sennheisers. So the small sound improvement of the Fostex would be washed out by its greater noise leakage, and the greater sound insulation of the Beter would give overall better listening in the situation of a noisy room
I love the T 5 p. However, more recently, Astell&Kern came up with a variant of the T 5 p tuned to their own digital music player. I've heard it and compared it to my T 5 p. It does sound better when driven by the AK240 player and using the equalization preset they have for the AKT5p. Not sure how it would compare if I were not using the A&K source and preset.
