Boomers obviously, but it's ironic that after 28 years of Boomers, the Presidency went to an older generation.
Someone born in 1942, like Biden, is much more of a "cultural Boomer" than the Gen Jones'ing Barack Obama. Clinton, Dubya, Trump and Biden were all born in a 4 year period between 1942-1946, so they have in common the experience of coming-of-age in the most turbulent years of the 1960s.
Obama, in contrast, barely remembers the 1960s and began his career as an '80s yuppie. That's a different cultural planet. If anyone is the odd man out in this case, it's Obama rather than Biden.
Anyway, our popular conceptions of "generations" are too long. Someone born in 1945 has nothing in common with someone born in 1964 even though, by some definitions, they are both "Baby Boomers." I suggest we update the American generational chronology as follows:
G.I. Generation: 1915 to 1924
Silent Generation: 1925 to 1936
War Babies: 1937 to 1945
Baby Boomers: 1945 to 1953
Generation Jones: 1954 to 1964
Generation X: 1965 to 1976
Generation Y: 1977 to 1985
Millennials: 1986 to 1996
Homelanders: 1997 to 2005?
Zoomers: 2005 to 2015-ish?
If you notice each of these cohorts is about 10 years, which I think makes a lot more sense when we already tend to think about pop culture/events/politics on a decadal scale.