Main content on different site or utilizing one-page design?

[semaph0r]

What behavior would you recommend?

Case 1: Every action will load a new page
If the user clicks on a preview tab this will load a page on the left with e.g. all related bands and their short descriptions.

Case 2: We utilize a one-page design
We exchange the content in it's designated <div id="content"></div> loaded via javascript and leave the page itself untouched.

One argument to provide different pages is, that it would be trivial to provide all other build-in template variables which may change after user action. If we use the one-page design I'm not really sure how to achieve that.