I've always felt the transition years of 59-62 were the most interesting, in terms of looking back at style and culture here in the States.

The 50s seemed to be a decade of optimism, post-war in the States, and it was all innocent enough before getting into the indulgences and excesses of the later 60s.  Stateside, you had the birth of garage rock, which was sort of our homespun version of being "mod" without actually referencing UK mod.  Guys in the garage scene wore very "mod" clothes, which happened to be the hip style of the day so it's no surprise, but smartness definitely reigned supreme.  And the garage sound was probably the first true precursor to punk (even tho it can be argued that rockabilly was the first punk rock sound)....listen to tracks by The Wailers or The Sonics and you can hear the foundation that was to become the punk rock beat.

Style-wise there's no surprise shows like Mad Men intrigue clothes whores so much.  Everything was sharp and pressed without the boxiness of the 50s, and just embodies a "cool/hip" lifestyle that there seems to be a longing for these days.  Look at the popularity of painter Shag, who's images all invoke that early 60s "jazz/bossanova' hepcat that's too cool for school. Maybe contemporary life has become so much rubbish in terms of visual style that we all harken back to the atomic era when it seemed everything revolved around "being hep". (unless you were a square of course)