Service pack for SQL 2008 R2?
While most of us are aware on this answer, I thought to write a quick post on this as I was asked this question multiple times in past. Do we need to apply 2008 Service packs (SP2) on SQL 2008 R2 instance?
SQL 2008 and SQL 2008 R2 are technically two different versions of SQL Server. Hence you can not apply SQL 2008 service packs on a SQL 2008 R2 instance. If you try to do so, installation will abort by reporting that no upgradeable instance or shared feature is available on the computer.
Hence as of today, while you should apply SP2 on your SQL 2008 instances, there is no service pack required (or available) for SQL 2008 R2 instances.