I buy a lot of mine at Neiman Marcus, house brand.  I've found them to be good quality, they feel great on the feet, and are a good value.  Not sure if they ship to Australia, but here's a link:

http://www.neimanmarcus.com/store/catalog/templates/P9.jhtml?itemId=cat15550738&parentId=cat14030733&masterId=cat14120827&cmCat=

I also buy from Brooks Brothers (Golden Fleece), Ralph Lauren, and I often pick up Pantherella, but I must say, I prefer the Neiman to Pantherella.  May just be my unsophisticated palate when it comes to sox..

Interestingly, Cole Haan (which I buy from Saks) has a decent line of sox which are made in Japan.  Great patterns and colors, and pretty well made.  You can order them online also, but I'd order 2 or 3 pair and see how you like them first:

http://www.colehaan.com/colehaan/catalog/category.jsp?categoryId=300282#page=1,viewAll=FALSE,howMany=20

Jesus, that's horrible?  $70 for a pair of sox?  Even the Pantherella I buy at NM are usually available for less than $20 a couple times a year! 

I am of the mind that fairly decent sox can be had relatively cheaply.   In fact, its the one area of my wardrobe I don't pay a ton of attention to, and they are almost always impulse buys.  I was pleasantly surprised to find the NM house brand work so well for me, as they are very inexpensive, allowing me more $$ to throw at my shoe collection.