Since many people will use Excel regardless of how good other BI and DV tools are, I am regularly comparing abilities of Excel to solve Data Visualization problems I discussed on this site. In most cases Excel 2003 is completely inappropriate and obsolete (especially visually), Excel 2007 is good only for limited DV tasks like Infographics, Data Slides, Data Presentations, Static Dashboards and Single-Chart Visualizations. Excel 2010 has some features relevant to Data Visualizations, including one of the best columnar in-memory databases (PowerPivot as free add-in), an ability to synchronize multiple Charts through slicers, a limited ability to drilldown data using slicers and even the support for both 64-bit and 32-bit. However, when comparing with Qlikview, Spotfire and Tableau the Excel 2010 feels like a stone-age tool or at least 2 generation behind as far as Data Visualization (and BI) is a concern...
That was my impression until I started to use the Excel Plugin, called Visubi (from company with the same name, see it here ). Suddenly my Excel 2003 and Excel 2007 (I keep them for historical purposes) started to be almost as capable as Excel 2010, because Visubi adding to all those versions of Excel a very capable columnar in-memory database, slicers and many features you cannot find in Excel 2010 and PowerPivot and in addition is greatly improving the functionality of Excel PivotTables and Tables! Vizubi enables me to read (in addition to usual data sources like ODBC, CSV, XLS, XLSX etc.) even my QVD files (Qlikview Data files)! Visubi, unlike PowerPivot, will create Time Dimension(s) the same way as SSAS does. All above means that users are not forced to migrate to Office 2010, but they will have many PowerPivot features with their old version of Excel. In addition Vizubi added to my Excel tables and Pivots uniques feature: I can easily switch back and forth between Table and PivotTable presentation of my data.
Most important Visubi's feature is that all Vizubi's tables and pivots are interactive and each piece of data is clickable and enables me to drill down/up/through my entire dataset:
It is basically equivalent or exceeded the drilldown ability of Qlikview, with one exception: Qlikview allows to do it through charts, but Vizubi does it through Tables and PivotTables. Visubi enables Excel user creates large databases with millions of rows (e.g. test database has 15 millions of rows) and enables ordinary users (non-developers) easily create Tables, Reports, Charts, Graphs and Dashboards with such database - all within familiar Excel environment using easy Drag-and-Drop UI:
Vizubi's Database(s) enables users to share data over central datastore, while keeping Excel as a personal desktop DV (or BI) client. See Vizubi videos here and tutorials here.
Vizubi is a small (15 employees) profitable Italian company and it is a living prove that size does not matter - Vizubi did something extremely valuable and cool for Excel users that giant Microsoft failed to do for many years, even with PowerPivot. Prices for Vizubi is minimal considering the value it adds to Excel: between $99 and &279, depends on the version and the number of seats (discounts are available, see it here ).
I suggest to review these articles about Vizubi: in TDWI by Stephen Swoyer and relatively old article from Marco Russo at SQLBlog .