Short answer: No. Enterprise is not required for TFS integration.
Longer answer: If you don’t have Enterprise, you don’t get Excel services. Without Excel Services, you’ll only get two dashboards built off SQL Server Reporting Services. With Excel Services, you’ll get five Excel-based dashboards. So TFS 2010 supports standard MOSS and even some free version of SharePoint, but the difference is in the dashboard experience.
Look at the Dashboard Requirements section of this topic: http://msdn.microsoft.com/en-us/library/dd578615.aspx
Basically there are two types of dashboards: most sexy and sexy. If you use any of the supported free version of SharePoint or MOSS 2007/2010 Standard, you get sexy dashboards. If you use MOSS Enterprise 2007/2010, you get super sexy dashboards.
I almost wrote supper sexy. Must be the picture of the beef.