This one is fairly well covered in Nikhil's Server Control Presentation, but I thought I'd mention it too. With Whidbey you can easily add images, script, etc to your server control quite easily. Gone are the days of requiring some “client files” folder on the server, because you can just embed your stuff into the assembly as resources, and use the built in WebResource IHttpHandler to get them out. Many people ( including me ) have been including custom handlers in their server controls to do this, but now I don't have to rely on web.config entries for the control to work. It Just Works. And not only do you get runtime availability of the resources, but the handler also works at design time! Awesome.