For tiles
http://www.tfo.com.au/
Be it that last time I called in they seemed to have changed staff so may have changed hands which could impact their previous good pricing.
For other bathroom things we generally use Osmans. He sells via Ebay but there is a show room in Auburn. I belief they have opened some others.
http://stores.ebay.com.au/OSMANS-HOME-IMPROVEMENTS
For Kitchens we us Payless Kitchens out at Hoxton Park. We manage the whole kitchen install even installing the kitchens ourselves and installing our own granite tops etc. As such you may not find them the best price for your situation.
One thing that is for sure is don't buy anything in the Shire as everything is too damn expensive.
Cheers
PS a previous thread re this same question
http://somersoft.com/forums/showthread.php?p=833498#post833498