Yeh I agree about the cost of the cradle huts thing - and personally, the thought of staying in huts like those with the linen tablecloths and critically-acclaimed wine in the middle of that wilderness is not something that particularly turns me on - but the fact is, it enables people who would otherwise be unable to see that magnificent area to do so. My mum and a coupla her mates did the cradle huts tour and couldn't rave about it enough.
Another stunning day walk you can do which is quite close to the start of the Overland Track is to an area called the Walls of Jerusalem, which is a little enclosed alpine paradise of cliffs, tarns, waterways, mosses and boulders, real fairytale stuff. More at http://www.parks.tas.gov.au/natparks/walls/index.html
Disclaimer: the following are not mountaineering or bushwalking related comments, so ignore them if you like. Agree with previous comments about the various 'streets' of Melbourne that give the place its character, they're spread all over the city, each with its own particular flavour. Make sure you check out Lygon, Brunswick and Acland streets as mentioned, but also Smith Street, Sydney Road, Chapel Street, Fitzroy Street (in St Kilda), Bridge Road, Greville Street (off Chapel), Carlisle Street, the list goes on. Yarra Valley is lovely for wine and while you're up there you can't miss Healsville Sanctuary for all of the types of local fauna in one spot (no crocs sorry we don't do those in Vic, best left to the cowboys up north). Not that I like zoos, but the Melbourne one has really improved its animal-friendliness (far fewer cages) - they recently knocked down a third of the zoo to build an elephant run. I'm sure you'll find heaps of info on stuff to do all over the web, but particularly check out what festivals are on since there's pretty much something every week. Oh and with apologies to Rick, don't bother with the Rialto Observation deck, you can go to the toilets on the 36th floor of the Sofitel Hotel (55 Collins Street) to get just as good a view for free