Well, I've voted for the 60's as this is the time when I started and also had my most successful season's racing.
At that time we were still quite naive about the continental scene and drug taking was something that happened but not really mentioned. Anyone who went 'sur le continent' either joined in, lived with it or came home bloody and defeated.
Time Trialling was in an era when fast times started to become more of a reality for the average rider with better diets and training techniques, the down side being the still very apparent intransigent attitudes of RTTC officials over advertising etc. 'You can't ride wearing that hat/jersey/shorts/shoes (delete where applicable)' was a common sound. Riders got 'Banned' for the most ridiculous petty 'offences'.
Road Racing was still able to use most of the national road network without to much traffic problems, even having right turns and crossing major roads (but when I started, 'Give Way' lines were still enforced which, if they were at the bottom of a big hill, could be difficult to keep to!). However, internationally the Brits (amateurs that is) were only 'adequate' in performances apart from a couple of notable exceptions but we did manage to win the Milk Race a few times!
Most of my 'Heroes' date back to this period, the continental ones (Rik van Looy, Jan Janssen, Tom Simpson etc.) were virtually unattainable and only seen in magazines - or the Isle of Man - not like today when cycling is available almost daily in the summer on Eurosport etc.
Sorry to ramble on a bit, nostalgia ain't what it used to be
Today is the yesterday of tomorrow.