I decided to take the time to download the latest beta of Visual Studio. Below are my impressions from initial usage. This mainly means I opened the environment and played a little.
The first thing that you notice is that the IDE looks essentially the same as it did for VS2005. When you create a new project you will notice that there are now options for WPF, WCF, WF and AJAX projects. Seeing as I spend most of my time in web applications I figured that would be a good place to start.
It is good to see that I no longer need to worry about downloading a separate install to have a project file created for my web applications. This was a pet peeve of mine.
The first feature that truly got my attention was the Split button in the designer window. This allows you to have a design view and a source view of your web page at the same time. Since I am often flipping back and forth between the two this seems like it will come in pretty handy.
I am still not thrilled that web projects run under the ASP.NET Development Server (File System) instead of IIS by default. I would prefer that it took fewer clicks. It leaves me longing for the .NET 1.1 days where it would setup a VirtDir for you automatically. Of course I had problems with that as well, since I didn't want to put the physical files under InetPub.
Of course there is now a LINQ data source. This is something that I intend to do some experimentation with in the future.
In all the changes don't rock the world, but they are cool and helpful. For more information check out Scott Guthrie's post about ASP.NET AJAX in VS2008.