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Turtle Beach X41 (Wireless, Xbox 360, 7.1 Surround Headphones) for $89.95 + $8.95 shipping from COTD.
I got these a few months ago from amazon, which was about $120AU. They are really good headphones, but you do get some interference from wifi (clicks and pops when a new device connects), but not often in my experience.
These have been replaced by the X4, but reviews say these are better than the X4's.
It's simulated 7.1 surround sound, but is very good.
Got a mate who paid ~full price for these and says they're worth it… so I'm guessing they're good :)