Like SharePoint 2007, SharePoint 2010 comes in three different versions.  However, the version names have changed and what is available in each version is different.  So if you’re moving from the SharePoint 2007 world to the SharePoint 2010 world, it can be a bit confusing (it has been for me).  The versions are:

• SharePoint Foundation 2010: This is the version freely included with Windows Server and is comparable to Microsoft Windows SharePoint Server (WSS) 2007.  It includes many of the basics and may be all that a small business needs to get started with SharePoint.
• SharePoint Server 2010 – Standard: This is the next level of SharePoint and includes important features such as Enterprise Search and My Sites (including the social media components) that most businesses will find important.  This is comparable to Microsoft Office SharePoint Server (MOSS) 2007.
• SharePoint Server 2010 – Enterprise: This adds more functionality to Standard including better business data connectivity (for connecting to CRM and accounting applications, for example), Excel Services (for showing Excel info in SharePoint – very nice functionality for allowing users to create their own enterprise dashboards), and a number of other advanced workflow management, Office integration and analytics tools.

Below is an attempt to summarize the different functions that are available in each of the three different versions of SharePoint 2010.  This is based on pulling data together from across the web and may not be complete or totally accurate.  If you have suggested changes to make, please feel free to do so.  I’ll try to keep this table up based on feedback (or, ideally, on something official that Microsoft may decide to publish on the topic).

UPDATE: Microsoft has published a slick SharePoint 2010 Edition Comparison page that has the latest and complete information on this topic.