"When compared to SharePoint 2007, one more search technology option - FAST Search Server 2010 for SharePointhas been added to SharePoint 2010 product family. Options now available are:
- Microsoft SharePoint Foundation 2010 search
- Microsoft Search Server 2010 Express
- Microsoft Search Server 2010
- Microsoft SharePoint Server 2010
- FAST Search Server 2010 for SharePoint"
This is a excellent blog post on seeing the strength of Fast search, a must read.