For me, it's close between a few "eras": 1963-1969, 1977-1983 and 1989-1995.
Very rough eras, of course. But the '60s psychadelic pop era, the British punk and post-punk era and the Madchester/Britpop/shoegaze era are all vying for my favourites (depending on mood). And by "Britpop" I don't...