I spent half a day last week playing with Flex and the new Adobe Apollo runtime. Flex was fun once I figured out the proper syntax for referencing XML data. The Flex scripting language is tag based, similar in structure to XML, but obviously with quite a bit more power. An interesting “feature:” Flex doesn't connect directly to a DB, but only to an XML data set.
You have to install an Apollo add-on to Flex to publish Apollo applications, but once that's done the process is a fairly painless “export” dialog.
As an example, I published a little Apollo application that reads in XML data from Candor Gallery. Obviously this is all alpha software, but my example was less than cross-platform as the Refresh button only works on OS X systems.
Nevertheless, from a development view, Apollo looks promising. Getting users to download the Apollo runtime will be another issue.