I'm not good at uploading pictures but we had an amazing seafood tower at Cafe Sydney, atop the Customs House, fabulous views. And if you are somewhat physically fit, the bridge climb is amazing!
Terry is right about Manly, it's a fun day trip. I would skip the Zoo and do Featherdale Wildlife Park as it focuses on Australian wildlife, and while the zoo is a great zoo, it's still a zoo. A trip up to the Blue Mountains would be a wonderful day too. You better plan a week in Sydney!