Microsoft has released Cumulative Update 1 (CU1) for SQL Server 2008 SP1, which is Build 2710. You can get it here. Fellow MVP Aaron Bertrand has an excellent post up that describes what you should do regarding this CU depending on what updates you have already installed.
The short version is that SP1 CU1 has the same fixes that are in RTM CU4, while SP1 by itself has all of the RTM CU3 fixes, plus six fixes from RTM CU4. Confused yet? Just read Aaron’s post. Microsoft’s Bob Ward recently wrote a good post that explains the relationship between SQL Server 2008 SP1 and the various CUs for RTM.
The right build to be on for a fresh installation of SQL Server 2008 is SP1 CU1 (IMHO).