Hey there fellow audio fanatics, I just wanted to solicit some opinions on which path to take. I currently switch between an unamped sony mdr-v6 and a stax srm001 mk2 setup at work. Both sound great in their own way, but I find myself constantly switching between the two - I love the bass/upper bass on the V6s along with the comfort, but I love the midrange and smoothness of the stax (though they seem to have a rolled off treble, and the bass is smooth but doesn't have that oomph and impact). I went to go audition some ultrasone proline 750s, but ended up listenign to the AKG k701 and sennheiser HD650s (driven off a headphone amp). I fell in love with the sound on both of them, and after some internal turmoil, decided to opt for the HD650s and a total bithead. However, another option that popped into my head was finding a used set of stax + amplifier on ebay, for a total budget of under $800. (I'm currently eyeing an SRM-1 with the SR-404 headphones) I constantly hear about the hd650s being one of the best headphones in the world, but I am a big electrostatic technology fan and have a special place in my heart for stax. Though to be honest - my stax srm001 mk2s did not really impress me too much. The Senn option would be nice in the sense that it would take the dac offboard to a digital usb device, and probably have a higher quality sound output than my macbook's onboard audio sounds. But the stax do have their own charm - and if I did get them, I'd use my macbook as the source using mostly lossless or >256kbit mp3/aacs. I'd love to hear your thoughts on these two options, and any advice would be highly appreciated!