Just to follow up on this, I'm really enjoying listening to my music with the D600's. I've bought the FiiO E11 portable amp and they seem to work well together, if a bit cumbersome to cart around outside the house. The headphones are revealing subtleties in my music that I hadn't heard before...

Thanks guys, really appreciate all the feedback and opinion. I have decided to go with the D600's. Just ordered them, looking forward to them arriving! Thanks again all.

Thanks guys. Trunks, what do the Denons have that the M50's don't in your opinion?

Thanks PurpleAngel. Have you tested any of the three pairs? As I mentioned, I think I would be happy to sacrifice some of the detail provided by the K550 for the more engaging bass of the M50 or D-600. My fear is that the K550's will sound flat or weak, especially since my source is an iPhone...

Hey guys, I am about to buy quality headphones for the first time. Narrowed it down to Audio-Technica ATH M50 (£130), AKG K550 (£130) or the Denon AH D-600 (£199). I have no experience of audiophile grade headphones and so am pretty naive regarding most of the technical commentary online. In...