For the Australian time servers on the Telstra network I use:
tic.ntp.telstra.net or toc.ntp.telstra.net. To save part of a second on DNS resolution time, or if the DNS server has not started I use the direct IPs in the setsntp command ie.
net time /setsntp:188.8.131.52
You can also use some other local servers like
ntp.cs.mu.OZ.AU. For other servers see here http://support.microsoft.com/kb/262680
This helps cure event log messages like