I know these can be cleaned using winapp2.ini but I don't see why they shouldn't just be in the standard winapp.ini:
Advanced Find > Search for the Word(s) drop-down list
RegKey HKCU\Software\Microsoft\Office\11.0\Outlook\Office Finder|MRU 1
Advanced Find > More Choices > Categories drop-down list
RegKey HKCU\Software\Microsoft\Office\11.0\Outlook\Office Finder|MRU 3
Mail Message > Address (To:, Cc:) autocomplete drop-down list
FileKey %appdata%\Microsoft\Outlook|Outlook.NK2
(shown for Office 2003, other versions may differ)