Robin Wright Parties With Hot New Fiance While Sean Penn Hangs with Charlize

It was the BATTLE OF THE REBOUNDS in Hollywood last night ... with Sean Penn and his ex-wife Robin Wright each hitting the town with their new hot significant others -- but who came out on top?

Robin hit up RivaBella on Sunset with her "Lone Survivor" fiance Ben Foster -- he's attractive.

Sean went to his Help Haiti Home gala with new rumored GF Charlize Theron -- she's also attractive.

It's been almost 3 years since Sean and Robin finalized their divorce, but you KNOW they're judging each other's rebounds ... because that's what exes do.

So, we gotta ask ...