The best in Melbourne is, I believe, Grain and Grape (
http://www.grainandgrape.com.au). They have a great range and knowledgable staff. They have stuff that you can't get anywhere else that I know of, such as Belgian candi sugar (sounds like a porn star, I know
). They also do demos of mash brewing once a month. I'm yet to attend, but the idea is magnificent.
The one that I frequent, however, as it's about 30 to 45 minutes closer to where I live, is Liquorcraft/Australian Home Brewing (
http://www.liquorcraft.com.au) in Oakleigh (formerly in Hughesdale).
While I don't think their range is as good, and their staff leave a lot to be desired as far as knowledge goes (I find myself in there as a customer and giving advice to other customers! You can also see a previous post about me asking about a particular line, to be informed that the guy behing the counter had tried it but stuffed it up because he hadn't followed the directions), they tend to have everything I need as a kit brewer.
Cheers,
Oliver