Idina Menzel & Taye Diggs. Idina has a nudge more talent, simply because it's Idina Menzel we're talking (taken on Rent, AIDA, Wicked to name a few), but they are just the cutest things ever. Both incredible people.
I can't believe no one has mentioned Anita Morris and Grove Dale. Donna McKechnie and Michael Bennett (probably the MOST talented Broadway couple) Gwen Verdon and Bob Fosse (ok,well,perhaps it's a tie) Natasha Richardson and Liam Neeson Carollee Carmello and Gregg Edelman Marin Mazzie and Jason Danieley And if they had stayed together, Marc Kudisch and Kristin Chenoweth would have been a rather talented couple.