I can query the current version from RuntimeInfo.Version. But I would also like to know what service pack is also installed. Do I need to just check the registery key HKEY_LOCAL_MACHINE\SOFTWARE\ESRI\ArcGIS\RealVersion. Or is there a proper ArcObject that allows such a thing?
This may be a better way then trying to read the registry key.
This page can be used as a lookup from version number to service pack.