My new found glory is Flex with Ruby on Rails. Although some may argue, I think this elegant combination has the potential to spearhead Web 3.0!!
Adobe® Flex™ 2 is a powerful application development solution for creating and delivering rich Internet applications (RIAs) across the web (Appolo will be its counterpart for the desktop).
Ruby on Rails is an open-source web framework that is designed for agile development and enhanced productivity. It favors convention over configuration.
If you are interested in a related discussion, head on to channel #FlexOnRails on irc.freenode.net.