I just had my gold SR325's refurbished by Grado. Good job for just $45. Anyway, these are still my favorites for serious music meditation, especially paired with my turntable/cambridge pre amp and the BeyerDynamic headphone amp. The warmer sound of most records really balances the timbre.
I have several other pairs of good headphones (use my more comfortable Beyerdynamic for movies and videogames, but usually still gravitate towards the grado for most music). The 325 is just fun, period. I'm usually skeptical of burn in times. I think in most cases with all equipment it's more a case of your ears becoming accustomed to the particular sound, but for these phones I really think the drivers do need burn in time. After a while the initial high end fatigue is goon and the sound becomes warmer and more detailed.
Still can't compare to the sheer near perfect bass and sound stage of my Beyer DT990 600ohm, but hey that's why there's more than one club in the golf bag right?