An online survery by credit card firm Visa has found that Thailand is the favorite Asian travel destination of Australians.  Thailand was followed by Hong Kong, China and Japan.   The survey also found that about 20 percent of Australians were unaware that Beijing is hosting of the 2008 Olympic Games.  In addition, the survey reported that Aussies were the most likely to travel alone from the nationalities polled, and Australians were the most likely to believe that no countries were still severely affected by the 2004 tsunami.