Customers in Australia, including myself report no problems with using a US based web hosting provider such as Host Gator.
Because we now live in a global marketplace there is little problems. Server response times may be a fraction slower, so for website handling a lot of enquiries or requests from far distances may incur ping delay times. But you cannot beat the cheap pricing offered.
Also Australian customers note that you will be dealing in USD (United States Dollars) so please allow for a currency difference, depending on the exchange rate, you can check the Australian Dollar to US Dollar currency conversion at XE.com