Come on, fair dinkum. In terms of culture and lifestyle, Sydney doesn't even remotely compare to Melbourne. Melbourne is a beautiful, diverse city full of wonderful cultural adventures, like restaurants, music, art, beaches (well, you gotta drive 90 minutes down to the coast for real beaches, but whatever), and they have The Espy, The Prince of Wales, The Tote, The Forum and goodness knows how many other awesome pubs and clubs to see great bands in and all of these activities are within very easy reach.
Sydney? You have to travel for hours just to get anywhere. I really strongly dislike Sydney as a place in and of itself. An awful place and really, comparing it to NY or London is like comparing a fine dining meal to McDonalds. Sydney is a place that wants to be NY or London, but fails miserably. To put it in context, Sydney is to New York what John Howard was to George Bush - the dorky kid that desperately wanted to be liked by the cool kid, but just looked like a darn fool.