headphones grado rs1 or sennheiser650 or 600

Depends on what you want to spend. You can find Sennheiser HD600,s for as low as $299.00. I just purchased Sennheiser HD580's for $169.00 from Music Direct. They sound almost as nice as HD600,s. Web address, amusicdirect.com
VERY different sound. Lots of detailed reviews on head-fi.org. Most folks like or the other.