9 times out of 10, this won’t be quite necessary. In general, the end-users should be encouraged to learn to be comfortable with SharePoint’s full (read: clunky and rather complicated) user interface. Once the initial shock passes, the UI can be rather intuitive and helpful. That said, the full interface might not always be required, especially if a custom application is built onto SharePoint.
The following two links explain how the SharePoint Interface can be fully cleaned up. Aside from gaining a lot of real estate on the screen, any application running on SharePoint immediately looks a lot better. But of course, that is my opinion.
Removing left-hand navigation*
http://virtualizesharepoint.com/2011/03/31/removing-the-left-hand-navigation-in-sharepoint-2010/
Removing ribbon for non-administrative users
http://blogs.msdn.com/b/zwsong/archive/2010/04/29/how-to-hide-ribbon-from-users-without-edit-page-privilege.aspx
* This might bite you back in some scenarios, such as managing user groups in SharePoint (which makes use of the quick launch bar). My suggestion would be to keep a copy of the original master page handy (this should be done regardless).
PS: If like me, the only reason you need the quick launch navigation is to manage user groups then there’s an acceptable workaround. Rather than directly managing Site Users from the Site Administration page, manage them from the People Permissions page. This is a surprisingly easy way of getting around the issue. Note that I’ve only ever tried this with managing people – I’m not sure what else might require the quick launch.