I also think Hair Metal for the 80's
I should have thought of that. I find that genre amusing. Though didn't it enter its heyday in the 70's? (Not that these things can't cross multiple decades.)
and Gangsta Rap for the 90's

Ha ha. If I ever found myself in a
Quantum Leap sort of situation and I had the inkling that I'd ended up in the 90's, all I'd need to do is wait for a car to go by with its windows down and the latest gangsta rap hit booming from the speakers to be told which year it was. (And the name of the artist. Bonus!)
In terms of defining sounds, I think we'll need to get a few years our of the naughties first.
You're probably right. This is obviously a bit premature, it still being the middle of 2009 and all. I was just trying to see what we could conjecture ahead of time. (Sticklers for accuracy will actually point out that the end of the deacde is actually December 31, 20
10, but conventionally, we think of decades as years ending in 0-9 instead of 1-0.)
I was talking with my dad about this, and he said the 60's and 70's had just as many one-hit wonders and crappy songs. But as time has gone on, people tend to remember the best and forget the worst.
Every decade has one-hit wonders, but it seems to me that when something's brought back from the 60's or 70's, it's
usually something more enduring or classic, and yet when something's brought back from the 80's, it's often one of those campy novelty hits (or maybe the popularity of new wave at the time just makes it all seem like campy novelty to my ears). The jury's still out from the 90's. We had tons of forgettable music then, but it hasn't really experienced a resurgence yet. It'll be interesting to see if the folks who were kids in the 90's and who are just getting out of college now and who will hit their quarter-life crisis phases in the 2010's will bring us a wave of alternative rock/grunge revivalism (owing more to the early stalwarts like Nirvana and Pearl Jam, sans the rap/crunk style that took over rock at the turn of the century), we'll start seeing MC Hammer and Boyz II Men posters being sold for irony's sake at whatever mall stores capitalize on 80's nostalgia now, they'll revive the Lilith Fair (which will cause Sarah MacLachlan to actually put out her only new album of the entire decade), and they'll do a movie remake of
Friends with Seth Rogen in it.
In fact, did you know the #1 song of 1996 was "The Macarena"?!?! That's not what I would define as the sound of the mid-90's!
I think that one got extra play
because of its novelty value and its general obnoxiousness. After a while, there was something fun about getting that "Oh no they DIDN'T!!!" reaction when playing it at a party. Plus nobody probably wanted to buy an entire album by Los Del Rio or whoever the infernal artist was that came up with that thing, so the single moved a lot more units because of it.
I could totally see "Macarena" being played as an "establishing shot" for a film or TV show set in the 90's. That and "Who Let the Dogs Out". We may have all hated it, but we sure as hell recognize it.
NP: "Safe to Land", Jars of Clay