Dynamic Page titles with Layout Templates?

I’m trying to have one layout template to rule them all. Basically, how can I pull something like this off for every page?

{exp:channel:entries channel="news" limit="1" status="open"}

{layout=”site/_layout” title=”{title}” }

{/exp:channel:entries}

Or more ideally:

if layout template title is not set, use channel entry title. I can’t figure this out!

Edit: I realize that syntax doesn’t work, I’m just trying to describe what i’m trying to achieve here.