for RIA I use Flex: - http://examples.adobe.com/flex3/componentexplorer/explorer.html
plus open source libraries for flex: - degrafa http://www.degrafa.org/samples/foundation.html - axiis http://axiis.org/examples.html - BirdEye http://birdeye.googlecode.com/svn/branches/ng/examples/demo/BirdEyeExplorer.html if I don't need the full power of Flex, I use jquery UI http://jqueryui.com/demos/