duplicate templates?

Hi,

I want to build a site which has two nearly same layouts, the only different is that one layout have a header title segment and the other do not. The two layouts like:
layout1:

<br /><html><br />  <body><br />     ...<br />     <div id="content_box_left"><br />      ...<br />     </div><br />     ...<br />  </body><br /></html><br />

layout2:

<br /><html><br />  <body><br />     ...<br />     <div id="content_box_left"><br />       <div id="body_header">...</div><br />       <div id="body_contents">...</div><br />     </div><br />     ...<br />  </body><br /></html><br />

If I choose layout1 as the template, I have to put the <div id="body_header"> and <div id="body_contents"> into the resource content of every page which has layout2 layout. This seems not good. Do I have to create two templates, one is for layout1, the other is for layout2, but they are nearly same?

One way to go is to use one template, but two different CSS files to control the layout and put the path to the CSS file in a template variable.

Another way would be to put the header title stuff in a chunk and use a template variable to determine whether the chunk is included or not.