Hi,
depends on how different you want the pages to be I suppose. You could create 3 different pages and then have pagelayout.tpl import the appropriate one based on the user. Or you could have one template and hide/show parts dependant on the user. You need to consider that just not showing the links to content dosent prevent access to it - you will need to make sure your roles etc provide that security if you require it.
Heres a sample bit of code which we use to show the login/logout button dependant on wether the user is recognised or just anonymous - which may be useful.