Hmm, good question and I think it is very difficult to quantify.
In my experience (travelled and lived extensively in US) i have found that racism in Australia (specifically referring to black/white) is less overt against that particular group.
But there is definately amongst some people, a covert and subtle line of racism that runs deep, and it is very sad. It shifts towards various groups at particular times in our history.
It certainly isn't all encompassing though, and many cities/universities or even country towns will give you very little problems at all. But it would be silly to deny it doesn't exist.