I use Interactive Brokers too and am happy. They have cheap brokerage and much lower margin lending interest rates - currently 4.962% (BM + 1.5%) on amounts less than 150k, then 4.462%.
You can transfer funds to an IB Australian bank account to fund your account. You can trade overseas markets and hold your funds in other currencies if you like.
The main problem is that they don't use CHESS. I don't think there is a safety issue (there have been plenty of threads about it on this and other forums), but I don't know how SPP's etc work. Apparently you can participate in 'Corporate Action's but I haven't had to try it yet.
