Vista - Standard Logon Screen - Sort of

You can get back to a logon screen more similar to the originals with the
following:

Administrative Tools_> Local Security Policy
Then go to the Security Settings -> Local Policies -> Security Options and
in the right hand pane find the "Interactive Logon: Do not Display last user
name"

Enable that policy and logoff and give it a try.

Someone else mentioned if you want the control-alt-del behaviour go to start
then type: "control user passwords2". On the main tab you can require users
to enter name and password (not sure if that is required for the first thing
I mentioned to work). On the advanced page you can find the option to
require ctrl-alt-del.