I own an SR80,and i love it out of my Zune and my Chaintech AV710 soundcard.
It especially rocks out of my old Realistic STA2100D (made by Pioneer for RadioShack in the late 70's and early 80's).
The right amp does improve these,but even without an amp,for the price nothing really beats it. Maybe something out there is equal,but different i think.
If you plan on a recable someday, then get the 60's because the 80's are just 60's with a 4 wire cable and different ear pads. Same drivers and enclosures etc.,oh and 80 on the buttons instead of 60...lol.
They should definately be on everyones list to own for an inexpensive entry into audiophile headphones. They are better for music that is fast and punchy,rather than laid-back classical etc......theyre detail phones more than smooth and mellow and warm......but really you can play anything through them. Sometimes i EQ them a bit for stuff.
They probably sound best with tube amps,as the Grado family likes tube equipment and turntables,and possibly designed them around this sound.
I own all the headphones listed in my profile and always go back to my 80's eventually. Ill still buy other phones,but for some music ill always use my 80's!