MELBOURNE DUBBED the hippest city in the Southern Hemisphere, Melbourne is set for a bumper 2006. It hosts the Commonwealth Games in March, one of the biggest parties outside the Olympics, and next winter England play Australia at cricket there in a bid to retain the Ashes. GARETH HUW DAVIES finds his scorecard full of things to do for Pounds 100. 1 SPORT AND THE CITY THERE'S still time to book tickets for the Australian Open tennis (January 16-29, from Pounds 33 for two, www.australianopen.com.au) and the Commonwealth Games (March 15-26, www.melbourne2006.com.au). Tickets for the athletic...