Theming

Hello, I have a question about theming. I basically want to change the entire look and feel of the site (not that it looks bad or anything!). In addition I want to add features like a Facebook Style Header Bar instead of the navigation bar on the side and so on. What is the best option here? Installing a plain new theme and rebuilding the site's look and feel from scratch? Subtheming? (I did some tests but found it quite restrictive) Any better idea? Also I looked at the tutorial on subtheming. Did you change the structure since then? Because my page.tpl does not look the same. It only has the php print staements. Had to use platon--header.tpl to replicate the example. Thanks Shibbn P.S. You guys really did a great job with this!