My personal opinion is that Flash is superior for really quick and dirty functionality, like animating images and providing audio on a website, and from a business perspective it's usually a better investment for a lot of interactive firms because their designers can crank out fairly professional dynamic interactive flash pieces faster than it would take for someone to hand-code something with a lot more flexibility.
But with the rising mobile market I think people are starting to be a little more open-minded about silverlight and javaFX, especially as the IDEs for these have evolved.
In my personal opinion, I'm getting old and cynical and hate having to pay for constant updates to Adobe's Creative Suite, and have slowly transitioned into more of a developer than a designer, so my vote always goes to the open-source solutions, and since I develop in Java I have a JRE platform instance running most of the time. But I agree with Thorbjørn Ravn Andersen that the recent changes in Java are potentially game-changing, and we'll see some drastic changes in the market soon.