I'm a fan of Centrebet for all round use - they cover a huge range of sports, from AFL/NRL to Darts... they offer odds on sports you never thought existed! They also have an online poker site, but only international users can use it as online poker is illegal in aus!

If you want the best odds available Betfair is normally the way to go, other than Betfair the odds that are put up differ from bookie to bookie and its probably an idea if you're a serious punter (not like me) to get multiple accounts across many bookies. TAB is probably the worst excuse for a bookie known to mankind, they take a huuge commision out of the pool which really gets on your nerves after some time, they offer few events and are often slow to price up. The sooner Betfair takes over the bulk of gambling proceedings the better

Happy punting
Betsy