New Headphone User

Due to family considerations, I recently bought a new pair of Sennheiser HD600 (with stock cord) for a great price here on AudiogoN. As my preamp already has a build in headphone amplifier, I did not have to purchase one. What a fantastic purchase! For $259 I have outstanding sound with no room interactions and I can listen however loudly I wish without disturbing everyone else. Also as a bonus, the sweet spot is a 10' radius.
I am posting this because I am actually shocked at the fidelity one can obtain in a pair of headphones that, relative to my system cost, is inexpensive. How many of you have headphones and what are your impressions compared to listening through your speakers?

David