Most discussion of tax history mentions the top marginal rates of the past (91% in the 50s, 70% in the 60s and 70s, 50% through most of Reagan's presidency, etc.)

I like to highlight a different aspect: leaving aside what the rates were, where did they kick in? We live in times where people argue "are couples who make $250K 'rich'?" "Should we raise taxes on people who make over $250K? Over $500K?"

Where did these sorts of things lie in the past?

Using the inflation adjusted historical tax bracket tables from The Tax Foundation for married couples filing jointly, let's break it down a little and find out the equivalents in 2012 dollars:

1945:
Total number of brackets: 24
# of brackets only affecting income over $250K: 14
# of brackets only affecting income over $500K: 9
Top bracket affects income over: $2,551,044

1955:
Total number of brackets: 24
# of brackets only affecting income over $250K: 16
# of brackets only affecting income over $500K: 11
Top bracket affects income over: $3,426,776

1965:
Total number of brackets: 25
# of brackets only affecting income over $250K: 13
# of brackets only affecting income over $500K: 8
Top bracket affects income over: $1,457,740

1975:
Total number of brackets: 25
# of brackets only affecting income over $250K: 9
# of brackets only affecting income over $500K: 5
Top bracket affects income over: $853,509

1985:
Total number of brackets: 15
# of brackets only affecting income over $250K: 1
# of brackets only affecting income over $500K: 0
Top bracket affects income over: $360,650

1995:
Total number of brackets: 5
# of brackets only affecting income over $250K: 1
# of brackets only affecting income over $500K: 0
Top bracket affects income over: $386,423

2005:
Total number of brackets: 6
# of brackets only affecting income over $250K: 1
# of brackets only affecting income over $500K: 0
Top bracket affects income over: $383,773

2013:
Total number of brackets: 7
# of brackets only affecting income over $250K: 2
# of brackets only affecting income over $500K: 0
Top bracket affects income over: $440,876

Special Bonus Gipper edition numbers:
1988:
Total number of brackets: 2 (No, not a typo. Two brackets)
# of brackets only affecting income over $250K: 0
# of brackets only affecting income over $500K: 0
Top bracket affects income over: $57,738
(There was a reason why Poppy Bush had to go back on his 'Read My Lips' line -- this rate was so low it was unsustainable (naturally, they crucified him for it). And every RWNJ wants to go back to this, or lower...)

ALL income tax progressivity for very high incomes was eliminated under Reagan, and has stayed that way ever since.