Microsoft Office 2010
I am very glad to be using Microsoft Office 2010, and I think most business users should be excited as well. A program that I use very heavily is Excel, and a number of exciting changes in the 2010 version make it even easier to use and take advantage of its many powerful features.
The 2010 version allows for more powerful data analysis, including PowerPivot, which lets you experience fast manipulation of large data sets and data integration. You can also maximize utility by using massive data sets in a file (up to 2 GB with 64 bit version), which allows you to choose to simplify or get into very granular detail based on what you want out of your data.
There are also improved recovery options in the new version. You can recover versions of documents that you may have accidentally closed without saving, and you can also engage in simultaneous collaboration, where you can work with other people in the same workbook simultaneously on your internal network or in the Excel web app.
These changes are just the tip of the iceberg in the improvements to this latest version of excel, but should give you a good idea of why this program has stood the test of time and continues to improve.
-Daniel Mastracco, PEI