I've been following this thread off and on for a while, wanted to see what people are recommending lately for close-back headphones?  I have the Mad Dogs at home, and I think they are superb for movies and gaming, but a bit bulky to schlep back and forth to work.  Currently at work I listen to music using ATH-M50s driven by a Little Dot  amp (and a Fiio for DAC), which were a nice upgrade when I got them, but now I'd like to try something different.  
Looking at closed-back to block out some background noise in the office (and to keep from over-sharing...).  I've tried the HD598s, which were really comfortable but were also quite transparent to background chatter.  I'm not a fan of headphones that accentuate upper ranges, as I find sibilance really annoying.  Also not looking for artificially boosted bass, from the headphones I've tried I tend to like a flatter response, it sounds more natural to my ears.
Any low- to mid-priced recommendations?