Which major crossover/event series had the most impact? Which had the least?

[QuinnFillory]

Crossovers and Event stories are a dime a dozen in DC Comics. Heck, they practically have a Crisis every year. However, some seem to matter more than others. So, which ones had the most impact and which had the least?

[Vordan]

Most:
CoIE
Infinite Crisis
Flashpoint
Dark Knights: Metal

Least:
Zero Hour
Blackest Night (Flashpoint pretty much rendered all of its effects pointless)
Invasion!

That’s my ranking for the linewide events.

[married guy]

Major impact would be:
Crisis on Infinite Earths
Man of Steel (Byrne's version)
No Mans Land
Emerald Twilight
MAYBE Flashpoint (as it brought about the disappearance of the Flash Family and heralded the New 52)

No impact would be:
Drowned Earth
Countdown
Genesis
Final Night (enjoyed the hell out of it, but ultimately everything ended status quo)

[Lee Stone]

For me:

Most-
Crisis on Infinite Earths
Legends
Zero Hour

Middle-ground-
Invasion (it made changes to characters in books I was reading, namely Fire&Ice and Max Lord, but didn't impact the Trinity or the wider DCU much)

Least-
Millennium (Harbinger had better success as a legacy of CoIE than as a New Guardian)
War of the Gods (should've been so much better... but it was forgotten as soon as it was over, if not before)
...and everything else...

[Adekis]

Crisis on Earth One probably had the most impact after Crisis on Infinite Earths - the first time the JLA met the JSA and began a grand tradition. What a great idea!