Install the "Editors" and "Net" groups that will give you rsync, ssh, ssh-keygen and cron.
The trickiest thing that I keep forgetting about each time is you have to run "cron-config" which adds the cron service to Windows, and without doing that obviously no cron jobs will be run thus making automatic backups impossible.
Warning about rsync/cygwin and using the -a archive switch.
It's a good thing I caught this because it doesn't work ri........