I've found fun headphone walls at:
- AC Gears on 8th & Broadway
- Dijital Fix on Bedford in Williamsburg
There are plenty of hi-end audio salons around Manhattan (and quite a bit in Long Island and North Jersey, too), but you will be hard pressed to find one that stocks a variety of headphone amps. I've seen them at Lyric, Stereo Exchange, and Sound by Singer, but they usually only cary one or two models at a time (or are actually stereo preamps with good headphone stages). I've never seen them at Park Ave Audio or In Living Stereo. As for headphones, you've hit all the usual suspects: J&R and B&H--They seem to stock the widest variety. Also, B&H has a lot of stock that is not on display; you have to ask for it. The aforementioned high-end stores seem to only stock Sennheiser, Grado, and/or AKG.
I know this is a very old thread but can you recommend some places to listen to and shop for head phones on Long Island, I am interested in hearing and purchasing higher end audio, such as HD800's, 812pro and HE560. Thanks in advance.