If I have widget.net domain, I assume users are going to type in either www.widget.net or widget.net and expect to get to the same place in either case. But taking that as a given which is best practise:In either case browser shows the url they originally enteredIf the user enters www.widget.net it should change to widget.net (widget.net remains unchanged)If user enters widget.net it should change to www.widget.net (www.widget.net remains unchanged)Also if have widget.com domain as well what should happen.(I know how to do this now using Amazon Route53 and Amazon S3, just not what I should do)
What is current standard practise for redirects of http sub/domains
dns
You definitely want to have one canonical fqdn. Which one you choose is just personal preference but all of the other ones should redirect to the canonical domain to avoid duplicate content issues and visitor confusion.