I have Grado 60s. Those and the 80s are nice because supposedly they don't need headphone amps to sound really good. However, the much nicer ones like the Grado SR-125 or Sennheiser HD600s need headphone amps to really show their true capabilities. The sound you get from these high end headphones often surpass speaker setups that cost thousands. It's basically a cheap way to get the sound of a $10,000 home theater system.