TripAdvisor has tallied 75 million reviews and opinions worldwide since its inception in 2000, now spanning 30 countries and 21 languages.

Last week TripAdvisor released the results of its Australian-focused TripIndex 2012 during a media luncheon at the Four Seasons Hotel, Sydney.

TripIndex calculated the cost comparison of an evening out for two people in its ten largest destinations throughout Australia.

Perth ranked as Australia’s most expensive destination, at an average of $430.83 per night.

The criteria for an evening out was one night’s accommodation in a four-star hotel, cocktails for two people, dinner for two with wine and a return taxi to the hotel.

“Perth’s premium hotel prices are the primary reason for the city’s costly position,” TripAdvisor director account management Grant Colquhoun said.

Wollongong listed as the most affordable destination for an evening out in Australia, while Brisbane and Canberra were ranked #2 and #3 respectively, in terms of expenditure.

TripAdvisor also announced the winners of its 2012 creative advertising challenge, with Tourism Northern Territory victorious across six markets; Australia, Japan, Germany, France, India and Italy.

As winners, Tourism Northern Territory will receive US$800,000 worth of click-based advertising on TripAdvisor.