I wouldn't plan on saying Goodbye anytime soon. Right now about 20% of users still use a browser that's 8 years old. So if we add that to the roughly 2 or so

I wouldn't plan on saying Goodbye anytime soon. Right now about 20% of users still use a browser that's 8 years old. So if we add that to the roughly 2 or so years it will take for the HTML 5 standard to be finalized and implemented in browsers you're looking at about a decade or more before we have a widespread HTML 5 user base. There is one potential savior and ironically its a plug in. Namely Chrome Frame. If Google continues to update it and aggresively push it we might see HTML 5 use much earlier. But that still depends on the success of Chrome Frame eclipsing that of Flash. Otherwise Flash is still the most widespread solution for RIA based pages and will be for a long time to come.