Return On Investment
As of right now, my Antminer S1 has been hashing nonstop for 147 days. It has generated a shade under 1 BTC. That's good enough for ROI!! This marks an important milestone for my case study, as it proves that money can indeed be made from entry-level mining. Hopefully my ROI timeframe will provide a useful yardstick for other investors, who want to know roughly when they will start turning a profit.
While I don't wish to discourage you, assuming that the electricity prices in the ACT are similar to NSW and that you have a 'time of use' meter, the S1 already consumes more in electricity during Peak and Shoulder times than it can theoretically make in BTC. Most of my S1's are gone and the remaining pair are awaiting their upgrade to S3+. Even the S3 is already in 'negative territory' during Peak electricity times (despite some compensation from solar panels). Looks like we need to either co-locate the hardware to some cheaper electricity place, or say goodbye to mining

Cheers
Just looked up some ACT prices, and they are significantly lower than in NSW (Power companies don't want to upset the pollies?!), so you should be still in positive territory (but it may be worth factoring the electricity cost in future difficulty rises). (Maybe someone in the ACT should start a miner co-location business?!)