Just for the record to share with you:
Office SharePoint Server 2007 with SP1 (32 bit)
http://www.microsoft.com/downloads/details.aspx?FamilyId=2E6E5A9C-EBF6-4F7F-8467-F4DE6BD6B831&displaylang=en
Office SharePoint Server 2007 with SP1 (64 bit)
http://www.microsoft.com/downloads/details.aspx?FamilyId=3015FDE4-85F6-4CBC-812D-55701FBFB563&displaylang=en
Note: You'll notice two executables: OfficeServer.exe 295.0 MB and OfficeServerwithSP1.exe 409.2 MB. The OfficeServer.exe is the full RTM version. The OfficeServerwithSp1.exe is the new special slipstreamed version which is RTM plus the SP1 (slipstreamed).
These bits can be used as trial to activate standard or enterprise edition. Note these should not be installed on existing SharePoint Server 2007. The separate stand alone SP1 should be used in cases of existing installations.