Wes Felter (who's been blogging longer than I have) has some interesting thoughts on the future of the web.
Hack the Planet: We can imagine that Google Chrome (and later, Safari and Firefox) will reach feature and performance parity with Flash Player/Silverlight. (It will be interesting to see what codecs Google chooses, since there's a tension between openness and performance.) At that point, installed bases and developer ecosystems will become deciding factors between the platforms. Flash Player and Silverlight each have an official framework (Flex and .NET) and IDE (Flex Builder and Visual Studio), but "the open Web" doesn't. While the combined ecosystems of the AJAX frameworks are probably larger than Flex, each individual framework is a much smaller community. Will Google endorse one or embrace chaos?
Felter's insights are spot on, imo.