Microsoft has released SQL Server 2008 R2 SP1 Cumulative Update 3. This is Build 10.50.2789.0, and it has 22 listed fixes. You must have SQL Server 2008 R2 SP1 installed before you can install this Cumulative Update. Especially since Microsoft added some new functionality (such as some new DMVs) to SQL Server 2008 R2 SP1, you really should be making your plans to get on the SQL Server 2008 R2 SP1 branch.

As always, I want to remind everyone that this update is only for SQL Server 2008 R2 (which is a separate major release from SQL Server 2008).

The Build matrix below makes the relationship between the builds a little more clear.

-- SQL Server 2008 R2 Builds                SQL Server 2008 R2 SP1 Builds
-- Build            Description                Build        Description
-- 10.50.1092        August 2009 CTP2        
-- 10.50.1352        November 2009 CTP3
-- 10.50.1450        Release Candidate
-- 10.50.1600        RTM
-- 10.50.1702        RTM CU1
-- 10.50.1720        RTM CU2
-- 10.50.1734        RTM CU3
-- 10.50.1746        RTM CU4
-- 10.50.1753        RTM CU5
-- 10.50.1765        RTM CU6  --->            10.50.2500  SP1 RTM
-- 10.50.1777        RTM CU7
-- 10.50.1797        RTM CU8  --->            10.50.2769  SP1 CU1
-- 10.50.1804        RTM CU9  --->            10.50.2772  SP1 CU2
-- 10.50.1807        RTM CU10 --->            10.50.2789  SP1 CU3

Personally, I like to try to stay current on Cumulative Updates as much as I can.