I'm trying out closed cans now after a long time enjoying my trusty hd800's.  I've heard the m50Xs at my local store and I like the audiotechnica house sound.  I've come across two that I really want to buy, the w3000 anv and the w5000.  So my question is what are the differences (if any)...

I'm planning on driving my phones out of a current onkyo receiver most probably a 876. It will mainly power my speakers but for much of my night listening/movie watching I'll use my phones. Does anyone know how a modern receiver functions as a DAC or DAC+AMP? If need be, Ill just use the...