Outputting Caching in a membership site

[eluser]a tired machine[/eluser]
How do y'all handle output caching on a site that has user login/logout? I'm meaning a situation where if you're not signed in it says "Log in" and if you are signed in, it says "Signed in as [username], Sign out" but everything else on the page is the same for whoever.

[eluser]Thorpe Obazee[/eluser]
You'll probably need to search the wiki and/or forums for partial caching.