Melbourne and the surrounds have plenty to rival Sydney. How about the Great Ocean Road, the Otways, the Dandenongs (okay, so Sydney has the Blue Mountains...), the MCG (where you can choose between cricket, its original purpose, or Aussie Rules football, or soccer, or rugby (league or union), or the occasional Commonwealth athletic game), the Australian Open tennis at Rod Laver, the Formula 1 Grand Prix at Albert Park.
We may not have the Harbour Bridge, but we make up for that with two elegant bridges: The Bolte and the Westgate. We don't have the Opera House but we do have Rialto Towers and the new Eureka Tower, either of which offer great panoramic views of the city. We have a bigger bay too - Port Philip, with some lovely beaches and nice little bay towns to stop at for a coffee.
And great food, as Deborah said. Approximately 1 restaurant
to every 30 people resident here!
We're closer to Tasmania, too, which is a wonderful place for a holiday. You could combine the two.