Microsoft Expression Web is what Microsoft FrontPage should have been all along, and the only shame of it is that it took Microsoft this long to get it right.
Among Web designers, FrontPage rightfully earned the status of a running joke. It generated bloated HTML jammed with proprietary tags; it was a terrible pain to use with FTP; and the mere thought of FrontPage extensions, those proprietary server-side additions that created more directory clutter and security issues than usable features, were enough to send people screaming into the night.
Small wonder Microsoft dropped the name "FrontPage" entirely and decided to pitch Expression Web as a wholly new application (although you can pick up Expression Web cheaper if you have an existing edition of FrontPage).
There's another successor of sorts to FrontPage called SharePoint Designer, but it's used to build sites only in SharePoint itself - Microsoft's enterprise-level collaboration tool - and isn't intended as a general-purpose web-design app.
Expression Web's interface and layout are still very much like FrontPage's: a tree for the site you're currently editing, an editing pane that can be toggled or split between raw code and wysisyg (what you see is what you get) editing, and so on.
This immediately separates Expression Web from the rest of the Expression suite apps, which look radically different; but by doing this, Microsoft has kept the best parts of FrontPage's classic look and feel to retain existing users, while at the same time retooling the program from the inside out to be strongly standards-compliant.
At the same time, there's enough backward compatibility with FrontPage-specific features in Expression Web that one can continue to work more or less seamlessly with older FrontPage projects. These features include the dreaded FrontPage extensions and web bots, which render content like page includes when the site is published to a remote host. Most people, though, will probably want to migrate away from anything proprietary if they haven't already done so.
What's immediately apparent as new in Expression Web is the presence of panels that let you edit and apply CSS (cascading stylesheets) styles as well as work with tag and CSS properties. CSS and XML are now deeply ingrained into the way you work with pages, not just added as afterthoughts. This stuff is also made that much easier to use courtesy of some intuitive GUI (graphical user interface) mechanisms.
For example, in Expression Web you can move a given CSS class from a page to a style sheet by simply dragging and dropping. If you want to wrap objects within a DIV or a SPAN tag, just select the objects in question, choose the 'div' object from the HTML toolbox and select Wrap. In older versions of FrontPage, you had the Quick Tag Editor (and it's still present in Expression Web), but it isn't as immediately useful as Expression Web's new methods for accomplishing the same things.
The HTML and XML generated by Expression Web is as clean and free of Microsoft-centric tags as it gets, which is a welcome relief. The functions in FrontPage 2003 to clean spurious tags (such as those generated by Word) are all still here, but if you're starting a project anew you'll be pleased at how things look.