We'll, no more worrying about installing a Service Pack for SQL Server 2008 and not being able to uninstall in the event of problems. Service Pack 1 for SQL Server 2008 now allows roll-back of the service pack without having to uninstall the entire application, which will reduce risk for DBA's and minimize down-time for data services consumers!!
Some additional feature of SP1 are:
2. Report Builder 2.0
This is a great addition to an already awesome product!
Here is link to SP1 download: