Business Intelligence (BI) is a huge topic in the new 2007 Microsoft Office system (note the official naming here - system with a small 's' !). We have a lot of new BI capabilities in Excel 2007 client with very rich integration with SQL Server 2005 Analysis Services, new cube functions, enriched features for pivot tables, charting and visual analysis of data. And of course, Excel 2007 Services delivered by Office SharePoint Server 2007 is going to expand the business scenarios for a lot companies while dealing with spreadsheets.
Channel 9 has a new video showing off some of the BI capabilities in Excel 2007. Have a look here.