I am doing some research on Unicode for a white-paper I am writing. Does anyone remember the first version of MS Office on the Windows platform that was fully Unicode compliant? Not having much luck Googling this answer out of the net.
office 97:
"The universal character set provided by Unicode overcomes this problem. Office 97 was the first version of Office to support Unicode in all applications except Microsoft Access and Microsoft Outlook®. In Office 2000, Access and Microsoft Publisher gain Unicode support. Microsoft FrontPage® 2000 also supports Unicode on Web pages, but text typed into dialog boxes and other elements of the user interface are limited to characters defined by the user’s code page." - Microsoft
url:
http://office.microsoft.com/en-us/ork2000/HA011382921033.aspx
Further to DanWoolston's answer, Microsoft Outlook 2003 was the first Outlook version to offer full Unicode support, so depending on your definition of 'Office' (seeing as there are so many different editions), your answer might be Microsoft Office 2003.
URL: http://office.microsoft.com/en-us/ork2003/HA011402611033.aspx