Sony.com uses responsive design. Notice how the primary navigation is folded into a single menu item for mobile and how the tabs change to a drop down for the smaller screen size.
The premium news website, bostonglobe.com, uses responsive design to make it's content available on any device. It's a great example of how to use responsive design with a large body of constantly changing content.
The website for Confab 12, a content strategy conference, has a responsive design. In a blog post (link below), Brain Traffic's Sean Tubridy, discusses content strategy and responsive design.
Confab website: http://confab2012.com/... (more)