I am convinced that Adobe Flex is probably the best framework available for building “ajaxy” websites today.

There are a couple of reasons why I feel this way after building several Ajax applications. The support for localization, debugging, browser-independence, slightly less restrictive security model, rich component framework, modular coding standards are all the plus points for using Flex. This definitely comes with a cost which is that it only works on flash player. Now that is not such a big problem, if you realize most user base uses IE and flash comes installed in IE or Firefox. The framework is free and is quite bug free.