Hey, another Aussie!
About the Titanium HD, I've had a few driver problems with them. Sometimes the computer doesn't recognise the card exist and thus does not play sound. Requires me to reinstall the drivers. Though, I have to admit...the virtual surround sound software is quite good for its kind. The Asus STX is a good card. In my experience, it doesn't have as many driver problems than the Titanium HD (assuming you use the UNiFied Xonar drivers).