Originally Posted by phallan
Alright (to both of you answering) thanks!
For the record I've been on the hunt for an upgrade for a month or so. The idea is to get a great set of headphones that can and will work smoothly with a dac/amp setup together with my MacBook Pro 13" Retina at work. So the mobility isn't a requirement this time, as it was with the m50, what is a...thing i need though..is a headphone that shuts the world OUT and keeps the music somewhat IN, hopefully this won't make the sound unnatural. When I decide on a headphone I want the quality of the sound to be the main focus.
So that sounds like you are only considering closed options. a lot of the headphones suggested so far are open (including the beyers 990, he-400, and x1) - aka better sound stage & sounds more natural, but leaks sound in & out...
the options suggested so far that are closed include the beyer 770, beyer COP, sound magic HP100, denon 600, and ATH-WS77
Great non-portable closed options to consider include the closed Mad Dogs (a bit above your price range) and the AKG K550 (go try it at best buy & see if you like it - very neutral pair of headphones with great sound stage, but some people complain it is too bass-light if it doesn't fit properly).
If you are solely looking at closed options, most of your other closed options will be portable as well.