I currently have a pair of the Sony MDR-7506. I like them fine, but I was looking for a headphone that offered more isolation, and it would be cool if they sounded even better than the 7506's too. I heard that Beyer was the way to go, but I didn't know which phones were better for what. I was looking at the Beyer DT-250's, but they come in 80ohm and 250ohm versions, and I didn't know if one was superior to the other or what, and that seems like quite an impedance difference. I was also looking at the DT-150's, cause they look like they would isolate very well, but I've never heard anyone say anything about them. Again, thanks for your help.