What are the options available for cross platform rich user interfaces development?

Question

Some of the requirements (restrictions) for such a ui framework/toolkit are:

• No single vendor lock down
• Ability for real time data visualization
• Good initial widgets
• Good dash boarding capabilities
• cross platform
• Good development/debug environment
• No flash

Answer 1

It's a pity you can't/won't use Flash. Else I could really recommend Adobe AIR. It has a good editor (Flex Builder built on Eclipse), a good component framework with many out of the box components, charting components set, ability to communicate with many different protocols (and you could write your own protocol implementation), cross platform, runs in the AIR runtime and not in the browser, file IO, ...