I made a similar upgrade a year ago buying some HD580's(still have my SR-80's though) But don't expect a huge improvement sonically, the difference is more subtle than you may think. The SR-80's are more colored compared to the HD580's, but not disagreeably so. The 580's are more transparent, and analytical. I prefer the Senn's mainly because of thier superior comfort, I love the way the 580's earpads envelope my ears("Set it, and forget it"), where as with the SR-80's I'm always fidgeting around with them. But it's nice to have both, if anything for comparitive purposes. BTW, the reason I chose the 580's over the 600's is because I couldn't tell any difference between the two(not to mention the $100 price difference), maybe I just don't have the "golden ears" some of the other Head-Fi members have?