I'm researching Office 12 at the moment. Looking at Office as a solution developer, things got really interesting with Office 2003. The core scenarios moved from document CRUD to include collaboration via Sharepoint integration and the Information Bridge Framework suddenly made the 'Office as Smart Client' concept more capable.

Well Office 12 ups the ante again with server based scenarios.......... oops, I had a paragraph of juicy information here but I've just checked and its internal only at the moment - sorry I'll just have to promise to come back to it soon. As a colleague told me, the office clients (word, excel, etc) are just the tip of a very large O12 iceberg.