I pretty much signed up so I could reply to this.
If you are thinking of Melbourne, look no further than Doherty's gym http://www.dohertysgym.com/. There are two locations, both are 24/7, the one I train at in Brunswick, about 15 min North of the Melbourne city centre, has 3 power racks, a monolift, a bench equipped for bands, 70 kg DBs, some bumper plates, kettlebells, heaps of Panatta and Hammerstrength machines and heaps of big and strong guys.
Just on the weekend there were powerlifters there doing 220kg 3 board presses for triples and doubles, there are heaps of bodybuilders that train there, and whats more the owner is the guy who puts on the Aussie pro Grand Prix, and the pros come and train at the gym whilst they are out. I've trained next to Toney Freeman, Ronnie Rockel (sp), Silvio (the guy who came second in the Aussie Pro this year) to mention a few. He also puts on the amatuer competions and the state titles.
The other gym, which I haven't been too, has strongman equipment - farmers bars, atlas stones, yoke and possibly more, and they have strongman comps.
Fitness First offer the chance to make decent money, as they have large membership bases, but they charge fairly high rentals and they often have too many trainers for the gym - ie it can be a scrap to get clients. But once you get going there is the chance to make some good coin. There are heaps of small private gyms that will give you the chance to make good coin though, worth checking out when you get here.
Hope that helps.