This is orders of magnitude better than Singapore for AUS/NZ.
Actually, for some people in AUS, West Coast US will be better than Singapore because some ISPs (eg TGP) route via the US to save money. [1][2]
Edit: Of course, Amazon are supposed to be launching EC2 (or just a CDN node?) in Australia sometime soon.
[1] http://akb.id.au/2011/amazon-ec2-latency-australian-soil (look at the Melbourne latency to Singapore)
[2] https://forums.aws.amazon.com/thread.jspa?threadID=45867