This was the version of the Excel which introduced the “Microsoft Fluent User Interface”: the menus and toolbars of the previous version were replaced by a Ribbon consisting of tabs, groups and commands. The File menu disappeared and was replaced by the Microsoft Office button (large circle at the top left of screen).
The chart wizard of previous versions has gone and, indeed, creating charts is one of the greatest changes in the product.
Similarly, conditional formatting has been enhanced and is almost unrecognisable from previous versions. If you like colours and symbols in your spreadsheets, this command is well worth investigating.
For security, macros are now stored in a special macro-enabled workbook and the Smart Art graphics introduced in other Microsoft Office 2007 products is also available in Excel.