Spectacular View!
On the 12th floor, the revolving restaurant (only one in Adelaide) serves great food, specialising in seafood. The price is a bit high, but you will not find a revolving view of Adelaide anywhere else while dining.
The best time to go to the restaurant is at dusk, so you can see what the Adelaide is like during light hours and then what it is like after dark. I think it takes about an hour for a revolution.