Yesterday ServicePack 1 for SharePoint 2010 (and also FAST Search Server for SharePoint) was released. Let me quote the main improvements:

Overview of SharePoint Server 2010 SP1 improvements


Specifically, these are the key areas of improvement in SP1:

  • Improved support for Internet Explorer 9.
  • Recycle bin: Lets you restore a site collection or a web that was
    deleted.
  • Remote Backup Systems (RBS) and shallow copy can decrease downtime and
    increase efficiency by moving pointers to databases instead of moving databases.
  • You can see which folders are taking up valuable space with the improved
    Storage Management feature in site settings.
  • Support for Microsoft SQL Server 2011.
  • A more robust Search Host Distribution service that improves error recovery
    and performance during the search crawl.
  • Adds backup and restore functionality to recover deleted site collections
    and webs.

Overview of FAST Search Server 2010 for SharePoint SP1
improvements


Specifically, these are the key areas of improvement in SP1:

  • Adds more flexible custom property extractors.
  • Adds Greek spellchecking and stemming.
  • Improves title extraction for Word documents and PowerPoint presentations.
    Titles are now presented correctly, and relevancy for Word documents and
    PowerPoint presentations is improved.
  • Improves default schema that improves relevancy.
  • Improves index backup and index restore.

 

List of all SharePoint 2010 and Office Server 2010 SP1 packages