I got a pair for x'mas, and I have to say that they are brilliant for the amount of money they cost (i.e. they're not a £200 pair).
The sound is very rich and warm thanks to a reasonable amount of mid frequencies, with a VERY powerful bass/bottom end that really makes it sound like the band is next to you in the room! They are very clear and I've heard bits of songs (like tiny detail) that I've never heard before since I've started using these!
And to top it all off, they are very light and comfortable to wear for long periods of time - so much so that you don't even realise you're wearing them!
They are very good for both music and spoken word (on DVD's etc). Also the noise cancelling is something of it's own...If you listen to a song reasonably loud (probably about 70/80% on an iPod) and start clicking your finger right next to your ear, you can only just hear it. By far the most powerful noise cancelling I've ever come across!
However, they are little bit heavy on the VERY VERY top-end (although that could just be my iPod or my hearing), meaning that "s's" can sound very "tss-y" on SOME songs if you get what I mean.
As well as this, the wire is too long!! It keeps getting tangled, but all in all, it's a small price to pay for such a good pair of headphones!
Considering I'm used to live music in a venue that has a state-of-the-art PA (I'm a casual lighting/sound/stage technician for a theatre), I would happily compare these to the main PA system (as in you get the same rich and powerful sound)!
By the way, if you really want an amazing listening experience, listen to 'David Guetta - Where Them Girls At' through these...I didn't like the song before I heard it through these!!