I think on these types of threads, many people romanticize a time when they were young free and single with no ties, no kids, lots of surplus income, no DH, no in-laws, no mortgage, clubbing every week til 3am, backpacking freely around the continents, travelling and working abroad, hopping from job to job, not having to worry about anything.
For me it was the 1980s. Wonderful decade for me in so many ways. I left school (which I hated,) I started work, I had my own money for the first time ever, I dated lots, I travelled lots, I lived in London for a while working as a temp, I lived in Paris for a few months, I lived in student digs for about 2 months - with a guy I was dating at the time, I spent a few weeks in New York, staying with a penpal, I had about a dozen friends, and I generally had a fucking blast. At the end of the decade I met my now husband.
The memories of the 1980s, from some people I know (particularly a decade older or more,) are high interest rates, strikes, wars, high mortgage rates, multiple redundancies, struggling financially, losing their home, marriage breakdowns etc etc etc.
So yeah, to sum up it up, there IS no 'best time' to be alive/to have been alive. It's all subjective.