I was there for pretty much two days - walked around the CBD shopping first, that was pretty cool. If only Melbourne Central was up and running! Myers still rocks though.
Take the free city circle tram right around the CBD, see if there's anything you'd like to look at, jump off it whenever. It's good for checking out what to go and look at.
Go up the really tall building (can't remember the name) on a fine day it's got great views, but the Coke up there tastes really weird.
Um, I wandered around the Gardens just over the river and some of the Botanical Gardens and had a bit of a snooze just to get away from it all before I flew home, but you're probably not into that!
Can't forget the Victoria Markets, plenty to look at there. Picked up some cool faceplates and stuff for my phone there too.
Ummm... That's about all I did really, but it could be cool catching a tram out to one of the not so middle of the city parts, I remember going somewhere with Laminge and the XA's before Raid 2 where it was just like cafes and stuff all down the streets, outdoor and all that. Nice place to eat.