I'm feeling a little under the weather today (have been all week - probably something I picked up on my travels) but noticed that Gary has posted a quick what's new in Expression Web 2 Beta. Embarrassingly I didn't know it was out there (I should have realised though having just been to Mix where Beta releases of other Expression products were announced). I've installed it but haven't had a chance to play with it yet.
Big changes seem to be PHP support, Silverlight 1.0 support, insertion of Flash and Windows Media files (including Flash preview in Design mode), Photoshop psd format support, ASP.NET AJAX support and support for the new ASP.NET 3.5 controls as well as improvements to FTP publishing. It now has a theme more akin to other Expression products (Blend, Design. Encoder) so it feels more like the others in the family. It's not a WPF application but it does require .NET Fx 3.5 and the Beta expires on 1/7/08.
You can download the beta here. All the Expression Product betas are available here. And I notice we now have Expression Forums where you can discuss and get assistance with the range of Expression products.