I'd like to throw out a theory:
I'd like to propose that most people know the 'music of a decade' by its representative genres - especially as they are retrospectively revived or rehabilitated in new music.
I remember when everybody hated the 70s: "Ooh, narsty cheezy pop music, electronic muzak and disco - DISCO! who the hell can listen to disco!' Then all of that got rediscovered in the late 90s, early noughties. We're just rediscovering prog rock: 'My god, Roxy Music was so advanced!'
http://www.guardian.co.uk/arts/frida...487397,00.html
I believe that Rap and modern soul will rehabilitate 80s styles faster than anything else (probably already have - don't keep up with those genres). The Smiths and Duran Duran and other New-Romantics are getting rediscovered, so all of that will go utterly mainstream in a few years. 80s metal is a safe bet. Madonna doesn't look a day over 30 (Hnnnf- fnarr!)
The great mystery is that Punk and Post-punk haven't had their true revivals yet. I think this is because they're still too 'socially' threatening for the American mainstream music industry (mebbe UK/Ireland as well). Gangsta rap, heavy metal, industrial all deal with hardcore sex, drugs, violence but most mainstream forms implicitly embrace the status quo. Sure it's tough on the streets, but when I shoot you and take your money and hos, the day will be brighter. I'm alienated and in highschool. My parents are existentially desperate hypocrites. A corporation owns my town. But when Mom lets me take my 12-gauge outside and I'm wearing my leather trench, I look just like Neo.
Watch-out. One of these days those really furious punk songs are going to sound totally fresh and mainstream: "God, how did we forget about The Clash/Black Flag/Husker Du/ The DKs? They're so relevant!" Unfortunately, when Denis Miller starts quoting Sid Vicious, we're all going to be really angry about a bunch of other things (the economy, civil unrest, wearing breathing apparati when we walk outside, etc.).