Comparison: SharePoint 2007 vs. SharePoint 2010
Here’s a comparison of Microsoft Office SharePoint Server (MOSS) 2007 and SharePoint Server 2010. Some features are improved in SharePoint Server 2010 while others are new. This Excel spreadsheet from Microsoft compares various features. The formatted worksheet makes it a bit easier to see the differences between the two versions. The ALL worksheet includes all the features on one page.
You can download the file here.