Being born in the early 70's I would say the Beretta 92FS/M9 would be the best to represent my generation as it was very popular and seen all over the 1980's. I identify with that decade the most out of any other.
I feel that the sub compact polymer guns like the Ruger LCP and the Glock 43 are what really represents my Generation (Millennials). The legalization and popularization of conceal carry exploded during the last 30 years, and damn near every gun company makes a sub compact polymer gun now.
A boomer hating to admit it is likely a Glock. I remember when it was “scary”. Word on the street was a plastic pistol that metal detectors could not find.
There were so many others, but they are no longer around.
Runner up, Ruger MKI, MKII, or MKIII pistol.