Hi,
A lot of couples are leaning towards more personalized weddings. With people getting married later, parents tend to be a little less involved and weddings can be a little less stodgy. I would second the suggestion you have a sit-down with the couple and find out what they're in to and what they're expectations are.
At one wedding I attended the couple's first dance was to "Fairytale in New York". The old gang had a great laugh. At another wedding, the joint was jumping when the band played "Secret Agent Man".
The last dance my bride and I danced to was "Will You Go, Lassie, Go".
Good luck!
Rich