WinCustomize.com take a look at Microsoft Office 2007 and its new UI. The article gives a more detailed first look including screenshots of what Office 2007 currently looks like under Windows XP vs. Windows Vista. The new UI is a major departure from the past:

The new Office includes a new user interface across all the programs that make up the suite. The title bar has been altered to have its own unique glass style with buttons that make use of the most common features of the application. The menu bar has been largely jettisoned and replaced by what are being called "Ribbons". Until I saw the most recent version of the beta, I was skeptical as to whether this was going to work out. But having seen it in action, I am converted. It really is slick. Gone are the "we know what you want" type UI behaviors and in its place are interfaces that streamline the entire experience.

The article also mentions that Word 2007 will support blog posting. To add to this, Microsoft has commited to having the HTML posted from Word be very very clean.

I think they really nailed it with these "ribbons" concept. Definately innovative, easy to use and looking just great with black theme. Wish more software would use this aproach. Microsoft never released any source or specs for XP or 2003 style of office toolbars. There were alot of developers cloning components with those styles but only only ones i know that really succeeded were DevExpress.com.

The only problem is the performance of/with such UI. It's clearly the "Next-gen" in user interfaces with updates happening allmost constantly when the mouse moves over a command. DirectDraw definately has it's work cut out with it but we'll see how it performs under DirectX in Vista (which is still very much a beta).