As for the Logout link,
I find that this is particularly useful when maintaining the site for client who does not want user registration functionality.
Customising Login links to User-friendly link
For those who are new to Joomla here are the steps to create a user-friendly link (or alias) for the login page. For example, user will be able to login via, http://<your-webpage>/login.
Its pretty straight-forward, so I've screenshot the steps below.
Customising the layout of the login page
If you are looking for the layout of the login form, you can FTP to /components/com_user/views/login/tmpl/ folder to edit the files.