The eighties thing seems to be more popular among the girls here. Guys are still into the more current hip-hop, boys in the hood kind of fashion, and that general culture is beginning to make it's mark in Japan, in fashion, music and attitude (though I think they still have a ways to go on that last one, which is probably just as well). Personally, I'm okay with that, but I can imagine many of you groaning at the thought, and I suppose I can understand your concern. So there are many kids roaming around in baggy pants, shirts and jackets, baseball caps askew or skull cap pulled firmly down on the head. They are pretty good at the "my pants are too low and they might fall off at any moment, which makes me cool" swagger, and their eyes look appropriately unable to open all the way, a la Snoop Dogg (and if you think I'm talking Charlie Brown's buddy, you've probably wasted your time reading this, sorry). This style goes quite well with the current infatuation with tuning up your otherwise-dull little cars (or in Japan, even vans and station wagons) that has taken the mainstream by storm since The Fast and the Furious came out a few years back.
The grunge thing hasn't really caught on, based on my limited view of Japan, but that is understandable, given the general Japanese aversion to anything that is or appears too old. However, that said, a fashion statement that embraces the old and worn-out would in some ways be far more rebellious or whatever than any of these other trends, if kids were so inclined. It probably has caught on at least a little bit in the bigger areas, but I haven't seen it.
Business men (or "salary men" in Japanese), still take the timeless approach with the suit and tie, and you can see tons of them everywhere, at almost any time. Likewise, "office ladies" have a similarly conservative dress standard, and are often about in standard suits, or knee-length skirts, and blouses, short heels, and nylons. Pretty standard, and nothing too fun to write about.
Then we get to juxtapose this all with the occassional trip to the traditional. A few weeks ago, I saw a young-ish family (husband, wife, and small child) apparently walking to a party or something. The man was in a suit, but the woman and child were in full-blown, traditional kimono and zori (like a slipper). They were just walking down the street, talking, with no readily apparent reason for the special wear, but every now and then you can see it, even outside of festivals.
It's an interesting blend of fashion tastes here, and we can't forget the school uniforms. Many kids, especially girls, oddly, where their school uniforms everywhere, and you can see them as well any time you see kids roaming around. It all makes for some good laughs sometimes, and there's plenty more out there that I haven't mentioned (punk, goth, the good ol' "none" that consists of just T-shirts and jeans, and such), but that's some of the more amusing things I've personally seen. I'm still holding out hope that someone will wise up on the eighties thing though....