I hear lots of votes for the Gold Coast...
Some of the big names in porn are based up in Brisbane. Companies like intergal.com, filthycash.com etc. Not sure if it would be a good idea to invite them to speak since they're affectionately known as the "Australian Porn Mafia". Might be OK as long as they keep the violin cases at home
Found an interesting article about it here -
http://www.lukeford.com/subjects/content/australia1.htm