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I don't know what exactly "best" means, but these are the ones I like:
Angela Bassett and Courtney B. Vance
Leighton Meester and Adam Brody
Ginnifer Goodwin and Josh Dallas
Rachel Brosnahan and Jason Ralph
Emily Blunt and John Krasinski
Angelina Jolie and Jonny Lee Miller (when they were together)
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Cassavetes/Rowlands
Your other two selections would be mine as well. I'd add Bogart/Bacall
I always had great affection for Lucille Ball and Desi Arnaz
They may not have been world class actors but they worked well off each other
They DID divorce after about 20 years so maybe this doesn't count...
Bogie and Bacall as well