I'd add the following to the relevant factors:
- do you mind fiat conversions (AUD to USD and vice-versa) which will most likely involve additional fees?

If you don't, than bitfloor is prolly your 2nd best option in my opinion.

I'd still go for MtGox though for high volume, especially if you're looking for a dedicated AUD market. If international wires for withdrawals still take a long time, you can always go for the voucher which can be cashed out much faster at aurumxchange or elsewhere. Personally I'm using bitcoin-24.com now to sell my bitcoins simply because it provides some important features for EU users (no transaction fees, very low FEE for SEPA withdrawals).

On a side note, totally unrelated, Stephen, is that picture the one taken from Mars surface?