As a general rule, I use a mix betweek HTML and Facelets tags in the layout pages. But for the actual content pages I try to only use the JSF tags available with my JSF library of choice (JSF + RichFaces).
That way I can have more control of which elements to show and hide, as well as the contents within each element, but I can still hard-code my main page layout in the facelets template file.
