I'm looking into creating a Rich Internet Application. For the interface, I want something smooth, fast, and robust. I realize there are several technologies out there to do just that (Flex, standard HTML/Javascript, Silverlight).
After using Grooveshark, I am very impressed with its interface (written in Flex). Personally, I don't think I have seen an interface written in standard HTML/Javascript that is that visually stunning, smooth, and fast.
However, I have heard many arguments against using Flex with many believing Flash will eventually fade away.
Anyway, I have seen solid applications built with each, and I know a decision can depend on many things. But, in general, what are the pros/cons for each technology and which one would you ultimately choose for your RIA?
NOTE: This would be an open web application with the intended audience being anyone. It's not being built for specific client(s).