You will not be disappointed with the HD600s. They are superb (wonderful sound-stage - very life-like reproduction - a great value). I believe a person would have to spend a fortune on source equipment (cartridge, tonearm, turntable, phono-preamp, and headphone amp) before the HD-600s would be the limiting component in their system. I drive mine with a SEX amp. I have an EROS on order (to replace a Music Fidelity V-LPS) . I'm currentlly considering an upgrade to my turntable (likely a VPI Classic 2 with Grado Master or Sonata to replace a CJ Walker 55, Linn Basik, Grado Prestige Gold 1 setup). I have not yet considered interconnects (another big chunk of change).
NOTE: The HD-600s are "open" headphones. You will hear outside noises and others will hear what is being played.