[markanini]

After all these years I'm still looking. The ER4 serves me great for the bulk of my listening but they're less conveniant when I need to take them off and put them back on quickly. Beyer DT250-250 was pretty close but I sold them due to the flattering effect on the sources which messed up my production work, plus the headband would quickly dig into my skull.

 

[flargosa]

The srh940 and dt 660 are the two closest headphones I have owned with similar sound to the er4s. The hd800 first version was pretty similar too but way more analytical and airy with a very 3d soundstage.

 

[Andrew_WOT]

HD800 are probably the closest but they are not closed.
 

 

[zowki]

The Paradox (modded T50RP):
http://referencesounds.com/paradox.html

Review:
http://www.headfonia.com/an-expensive-cheap-headphone-a-paradox/