If you'd asked this question ten years ago, the 'answer' would have been Java applets. Yeah.

Unless web browsers somehow become obsolete in the next ten years, you're looking at an evolved version of what we have now. HTTP, CSS, XHTML, and JS have plenty of room for improvement. It takes years for the standards to be worked out and longer for browser support, which is never 100%. Add a few more years for developers to take full advantage of the new capabilities.

What we'll have in ten years will be another iteration or two on what we have now.