Trent Walton, at the end of a larger piece on using media queries to detect screen height to adjust font size:
We’re leaping past any point where the word webpage makes any sense, and into a world where what is seen at any one screen size (or Photoshop comp) only captures a sliver of the display capability responsive websites muster.
I wonder if Responsive Web Design will diminish the role of Photoshop in the design process. It's hard to argue that the Adobe product dominates the industry, but my use has diminished over the years. Since modifying layouts in Photoshop is just plain tedious, Photoshop has been reduced to a stopover between Illustrator and the assets folder of my web project, lingering just long enough to get an adjustment layer (or two) and some layer effects.
Now, if in this brave new world designers need to create comps for multiple pages at different screen resolutions, I think the designers who can work in the medium of HTML+CSS will come out on top.