If you use FrontPage (or you know someone who uses FrontPage) - we have good news for you if you are considering upgrading your toolset. Expression Web provides a really solid Web authoring tool to create and maintain sites based on standards-compliant code. I have a non-technical friend (a theatre producer) who bought Expression Web on my advice (he was a hardcore FrontPage user), and he found Expression Web very easy to use and intuitive.
The Expression team has a great upgrade offer - if you purchase Expression Web between now and June 30 2008, you can receive a free 80 GB USB drive and a complimentary copy of "Microsoft Expression Web Step by Step"! Visit this site to learn more about the offer.
So where does Expression Web fit in with Visual Studio 2008 and SharePoint? Expression Web is primarily oriented towards client based programming and design - HTML, CSS and so forth. What's great is that you can take an Expression Web project and easily open it in Visual Studio 2008 (a perfect tool for backend/ASP.NET development). As you can see, the combination provides a really great Web designer/developer workflow.
If you develop content for SharePoint, a tool has been created for you called the SharePoint Designer which takes on a similar role as in FrontPage in terms of customizing the site templates and the "look and feel" of the portal. It's important to note that SharePoint Designer should be used if your site is intranet based or inner-facing. Expression Web is the right tool for any sites (including SharePoint sites) that are Web or public facing. Here is a diagram which shows you the logical decision point when considering what tool you would like to get.