WindowsPE, before HDD format: x:\windows\temp\smstslog\smsts.log
WindowsPE, after HDD format: x:\smstslog\smsts.log
Windows, SCCM agent not installed: c:\_SMSTaskSequence\Logs\Smstslog\smsts.log
Windows, SCCM agent installed: c:\windows\system32\ccm\logs\Smstslog\smsts.log
Windows x64, SCCM agent installed: c:\windows\sysWOW64\ccm\logs\Smstslog\smsts.log
Task Sequence completed: c:\windows\system32\ccm\logs\smsts.log
Task Sequence completed x64: c:\windows\sysWOW64\ccm\logs\smsts.log
UPDATE : I found much more at http://blogs.msdn.com/b/lxchen/archive/2009/04/03/a-list-of-sccm-log-files.aspx
