My ep-630s have decided to go very quiet lately. I've had the sennhieser cx-150s but gave them to my brother, the fit hurt my ear canal. I've been thinking about trying the JVC Marshmellows since they are said to be good for being cheap. I was also looking at the Astrotec AM90 after reading the review and looking at the list in the multi-iem thread.
Sources: Computer w/ realtek alc888 built in, Nexus 7, Motorola Triumph cell phone (unlikely), Sansa c250 mp3 player (riding bicycle). With and without a portable amp (pa2v2), and rarely using either the earforce dss or an old optimus sa-155 for my ps3.
Other headphones: ksc75 w/ quarter mod & loose clips (via cutting part of the solder joint cover off), portapro w/ quarter mod, and a bluetooth speaker.
Use: games, music (varies: Blackalicious, Weird Al, Tenacious D, The Planets Suite (classical), Piano, Violin, Ambient, Squarpusher, Miles Davis, noise/dubstep, The Chieftains, Paint it Black (Rolling Stones), and Jimi Hendrix), audiobooks, isolation.
I'd like to stay below $50, but I was looking at the RE400s too.