A few days ago, Microsoft released CU 5 for SQL Server 2005 SP2, which is Build 3215. This article outlines all the post SP2 builds that have been released. There are a lot more bug fixes in CU5 (Build 3215) than there were in CU4 (Build 3200).
Microsoft has improved the download request process (which is much better that the old way of having to call Microsoft Support), so that you can request the x86 and x64 versions of the update with a single request. Still, they should just make the CU builds publicly available on MSDN or TechNet rather that making you have to send in a request and wait for several hours to get a download link.