Jane Fonda, Angela Bassett & Jessica Lange, anyone? Seriously I'd consider leaving my husband for any of those women (and I'm straight).
Also, Gina Gershon is 56 and Marisa Tomei is 54. My 37 year old DH thinks they are incredibly sexy.
We also see older women IRL every day that we both look at with admiration.
I honestly think that as a woman ages she gains a sort of self possession, self awareness and confidence that is completely unmatched. Being so unapologetically yourself is damn irresistible.