The RC for GWT 1.5 has many new features, but one of the most fun is that the documentation is now hosted on a GWT program called the Google Documentation Reader. Check it out.
I used to be a fan of lowest-common-denominator web pages, hoping that if enough people worked that way then the browsers would make such pages look nice. Nowadays that seems highly unrealistic. Good design cannot be built into an automatic browser; there will always be an important role for site designers, and they need markup tools to do their job.
AJAX apps such as the ones Google puts out tend to be browser specific, but AJAX is the only practical way for designers to get the tools they need to make great web sites. If you are a holdout for having a single, browser-agnostic version of every web site, then a good challenge for you would be to go look at the Google Documentation Reader. Imagine browsing that information using static links...