According to this question we should discuss our site's style, including the color scheme and logo. These are a few of the questions we should answer:
It would seem to me as though the site should follow the new Ubuntu design. There is a design document available (supplemental to the Ubuntu Brand Guidelines) that outlines all the different logos, colors, and various elements and their meaning.
Personally I think some branding ala the Canonical standards is needed for the header to ensure users realise it is an officially supported Ubuntu site. However, I also think keeping it clean and simple like now is very very important because the basic stack overflow/exchange schemes are part of their success.
Therefore I would suggest the Logo strip be used, although I have to say I quite like the current light blue sketched logo!
How about half way between the two?