My favourite art store / gallery in Melbourne is Outre Gallery on Elizabeth St. They also have a gallery in Sydney. Head down there if you haven't already.
They specialise in low-brow, pop surrealism and retro art, featuring a few of my favourite artists of all time ... Yoshitomo Nara, Mark Ryden, Kozyndan, Tim Biskup and many more. Not so much in the way of local artists, though.
The store has a really unpretentious and friendly vibe about it, unlike many other galleries that you walk into. It seems to be run by people who enjoy their jobs and the art around them.
It's a very accessible gallery too, You can pick up framed prints for around the $100 mark, going upwards from there. Sometimes galleries can leave you feeling broke and hopeless when the lowest prices are around $4,000. I think a good model for a gallery is one where the everyday folk like you and me can afford to pick something up.
I think my gallery (if that's what it becomes) would probably have art at the lower price level, as Outre does. I'm probably thinking that I'd stock more work from Melbourne based artists though. Do you think that could work?