Elliot Jay Stocks:
I could go on about why I think Responsive Web Design is a great idea for your websites, clients, colleagues, and of course users, but the thought I’ll leave you with is this:
Create a new HTML document, add some content, don’t add any CSS, and view that document in a browser. What do you see?
The web has always been fluid; we’ve just wasted a good number of years forcing fixed pixels onto an inherently responsive framework. The time to stop is now.
It's an interesting and thought provoking article if you're interested in this stuff. Well worth the read.