As with everything it depends on what you want to spend. With the US$ being so strong lately though it's a great time to try some of the best Aussie hotels at pretty reasonable prices.

Sydney: Park Hyatt is probably the best hotel in Sydney. Great location, wonderful rooms, great service. Located almost under the harbor bridge the views of the city and Opera House are amazing and the rooftop pool is pretty sinful. The Regent is also excellent and one of those over the top asian hotels. Westin is probably the best value for the money in that it is a very nice hotel (yes one of the best in the Starwood group) but is a little more "business and group oriented" and doesn't have the flair of some of the other properties.

Reef: If you want show-stopping resort hotel, there is nothing better than the Sheraton Mirage in Port Douglas. Another choice is the Silky Oaks Lodge which is located in the rainforest and a real "luxury-adventure" type of place. But it is radically different in that it is not near the beach and doesn't have the same tropical resort feel as the Sheraton.

Melbourne: Like Sydney there are a number of great hotels here. I would vote for the Park Hyatt as a first choice, followed a close second by the Grand Hyatt. Park Hyatt is a little more intimate but the Grand Hyatt is another real show-stopper type of hotel.