Here’s a quick summary of what’s new, relative to Excel 2007:

• 64-bit version:
  If your hardware supports it, you can install the 64-bit version, which lets you create much larger workbooks.
• Sparkline charts:
  Create small, in-cell charts to summarize a range of data graphically.
  
• Pivot table Slicers:
  A new way to filter and display data in pivot tables.
• Pivot table formatting options:
  You have more control over the appearance of pivot table reports.
• File tab:
  The File tab replaces the Office button, which is located to the left of the other tabs. Clicking it displays Backstage View, a screen that lets you perform various operations on your workbook. This view essentially replaces the traditional File and Print menus — plus quite a bit more.
• Draft mode for charts:
  If you use many highly formatted charts, you can choose to display them in draft mode for improved performance.
• Conditional formatting enhancements:
  Data bar conditional formatting can display in a solid color, and the bars provide a more accurate display.
• Function enhancements:
  Many of Excel’s statistical functions have been improved in terms of numeric accuracy. The old versions of these functions are still available and have been relegated to a new function category called Compatibility.
• Image editing enhancements:
  You have much more control over the appearance of graphic images inserted into a workbook.
• Paste preview:
  When you copy a range, the Paste command displays various options (with preview).
• Ribbon customization:
  End users can customize the Ribbon by adding new tabs and groups.
• Equation editor:
  Create and display (noncalculating) mathematical equations.
• Faster processing:
  Microsoft made some improvements to the calculation engine, and files load a bit faster.
• New security features:
  Workbooks downloaded from the Internet or from e-mail attachments are opened in Protected View mode. Workbooks can be designated as “trusted,” and they don’t need to reside in special trusted folders.
• Updated Solver:
  Excel 2010 includes a new version of the Solver add-in.
• Enhancements to VBA:
  Many operations that used to require old XLM macros can now be performed directly using VBA macro commands.