Classic Eras for various car types?

While we were running the Around the World in 80 Minutes one-shot series, there was some discussion regarding expanding the series into a full month. I though it might be interesting to create a set of races that would run through a decade's most defining cars, on appropriate tracks.

It would either be a series in which people race a different car each week, or in which we run multi-class with different eras on the track at the same time. The specifics of how this series would be run (and I realize I'm essentially volunteering myself to do this) would depend largely on the month (whether we can squeeze five weeks in) and on the club activity at the time. A five-week month would allow running each week as a different "decade" (50's - 90's); high club activity would allow for multiclass racing to have a critical mass.

For now, I would like to get an idea of what people view as the "defining era" for various classes of cars. I'll give my first impressions as an example, and please feel free to share your own.

1950's - British Roadsters
1960's - GT Classics
1970's - American Muscle
1980's - Italian Exotics
1990's - Japanese Tuners
2000's - German Precision

These are of course really "soft" boundaries ("American Muscle" is sort of a late-60's/early-70's thing) and narrowing down the exact sets of cars would happen later.