Expression Web Designer has been out for a while and I am just not getting a change to play with it. So far I am pretty impressed. Upon opening it recognized all of the web sites I had opened previously in Visual Studio 2005. I was able to open them and it gave me a true WSIWYG type interface for pages built with XHTML and CSS. On top of that it recognizes all of your ASP.NET 2.0 controls such as GridViews, MultiViews and displays them accordingly. One cool thing it does is allow you to view a page in Design View and HTML View at the same time.
So far my only complaints are that it didn't recognize the use of the ~ specified in paths to my CSS files and it doesn't appear to support SourceSafe integration. That aside it looks like a great tool to do your XHTML editing with. It also doesn't support reading Global Resources (although it does recognize that the expression is there).
Go download it now.
Expression Web Designer