Hi totebride,
Shopping... one of my fave topics! Not too sure on what sort of clothes you're looking for and the budget you have, so just give you an overview...
1. Chapel Street.
Basically you get stuff thats available in the city area plus more! You have the mainstream retail stores like De Cjuba, Kookai, Witchery, COuntry Road, Review and Satch. If you're looking for something different, there is Zimmerman, Scanlan & Theodore, Bracewell (stocks Sass and Bide too!), Rosemin, Fat (has stuff from Gorman). If you have time, do check out Greville Street, which is off Chapel street, and about 10mins walk from the main shopping area. Average price is in the AUD100-250 range.
2. Smith Street & Fitzroy Street (parallel to one another).
At one end there are the Nike, Adidas, etc warehouses/discount stores. There is a pretty good varierty of stores here, from op shops to stores that stock Kate Sylvester. Venus & Mars... one of my favourites.
3. Brands Smart on Maroondah Hwy.
A discount centre for international brands. There were some pretty good buys here. However, I personally feel that if you're looking for 'interesting' and different clothes, this isnt the place to go to. But of course, this is just my personal opinion.
4. Chadstone.
Dont think you should waste your time here. Everything here is available in the city (if that is where you'll be staying). Unless you have too much time to spare, dont bother.
5. Bridge Road @ Richmond.
As nanshee said. Its affordable and there's stuff for everyone.
QV building in the city just opened and it has some nice shops like Cactus Jam and Christensen Copenhagen on the ground level. Also, if you were to go to St. Kilda beach, pop by at the shopping area, near MacDonalds. There are heaps of cafes there and some shops there too!
Let me know if you need the exact address of any shop or if you need any other info!