I am trying to get myself acquainted with the world of rich web application. There are some comparison tables of available technologies on the Wikipedia, but I still find it unclear what are the options for rich application development.

Could you please verify and complete the information I gathered below? What are the key pros and cons of each option? Which is the best choice for big and very rich web application?

Option 1: ASP.NET/ASP.NET MVC
Vendor: Microsoft
Environment: Visual Studio
Language: C#
Output: HTML+JavaScript+AJAX
Example: www.stackoverflow.com

Option 2: Silverlight
Vendor: Microsoft
Environment: Visual Studio
Language: C#
Output: .NET executable?
Example: ?

Option 3: Google Web Toolkit
Vendor: Google
Environment: Eclipse
Language: Java
Output: HTML+JavaScript+AJAX
Example: http://www.projectkaiser.com:8080/pk/

Option 4: Flex
Vendor: Adobe
Environment: ?
Language: ?
Output: Flash (.swf file)
Example: http://listen.grooveshark.com/

Option 5: Adobe AIR
Vendor: Adobe
Environment: ?
Language: ?
Output: AIR
Example: http://www.colabolo.com/en/download.html

Option 5: Ruby on Rails
Vendor: Rails Core Team
Envirnoment: ?
Language: Ruby
Output: HTML+JavaScript+AJAX?
Example: ?

Option 6: Java Applets
Vendor: Sun
Environment: Eclipse
Language: Java
Output: Java Applet

Option 7: OpenLeszlo
Vendor: ?
Environment: ?
Language: ?
Output: ?
Example: ?

Option 8: Python?
???

Option 9: XUL
???