SameSame has just announced the 25 Most Influential Gay and Lesbian Australians for 2008. Here they are:
If you click on that you will find the interactive version where you can find out more about each nominee. Some of them are very well known, though whether all of them were known as gay or lesbian by the general public varies.
In sheer popularity, not to mention terminal cuteness, it is hard to go past Matthew Mitcham, hero of the 2008 Olympics.