rukspc, I'm thinking along the same lines as Candc. You said they just got married, bought a new house and started a new job. Actually listing all that I wonder about a gift certificate for a couples massage. They both must be stressed.
Back to my original idea, how about a gift card to a store for house furnishings. Or you could give multiple cards to different stores. How about including a personal note acknowledging all the big changes in their life?