If you go during the end of their summer (I think early March/April), then surfee stuffs would probably be cheaper due to summer sales.
If you are interested in vase then they have lots of nice looking one there and affordable too (quality equivalent to those you can find in Takashimaya, but much cheaper).
As for wine, personally I like wines from Yarra (Victoria), Margaret River (Western Australia) and vineyards like Evans & Te, Rosemount Estate, etc. These wines are relatively cheaper in Australian than Singapore. If you can afford more, you can get very good wine.
Go to SMith Street Fitzroy for Nike, Adidas and other clothes makers warehouse. Cheaper, but out of season or odd sized items. End of summer / beginning of Autumn stock take sale normally end June early July.
A$ going up against S$.... One year ago, it was lower than S$ but now it is on the upward trend... 2 weeks ago, was A$1 to S$1.18 and this week at about S$1.21/2. I'm also waiting for the right time but it is not easy to predict. I will settle for S$1.20 as my holidays is coming up in Dec...