With the advent of HTML 5.0 and its support in such modern browsers as Firefox 3.5, Safari 4, Google Chrome(new betas) and Opera, the entire dynamic display framework provided in both Flash and Silverlight, becomes almost a moot point.
What I like about the possibility, is that it creates an open playing field that anyone with a browser can utilize, rather than only those that have purchased expensive development kits.
The whole write up on what HTML5 really is can be found at Wikipedia here.
Some shiney examples:
