I have been thinking a bit and there are a few reasons I like Microsoft’s new Silverlight technology.

1. One reason is that the Silverlight could potentially make the need for Windows Media Player on a host machine obsolete. During the week I removed Windows Media Player from a machine and tested a Silverlight application on it that uses video.
2. Silverlight is easy to host. You simply add a mime type to IIS. You can find a guide to doing that here.
3. Silverlight has a Linux implementation called Moonlight.
4. Integration with Visual Studio 2008. This is an important feature for an web/application developer because your C#/VB.NET skills can be used to develop and enhance Silverlight applications. XAML plays an important role here and bridges the gap between design and development significantly.