Unlike most people, I use quite a few of the advanced features. Plus I love Outlook 2003, the best e-mail client I have ever used.
Excel is great for the engineering ad-ins, complex number support is great.
And I from time to time use access either because I need to, or I need a quick personal relational database done up for whatever reason. (An SQL Server is not always appropriate).
I also use Microsoft Visio and Project from time to time for various things. So you can say I'm a deeply rooted Microsoft Office user.
btw, Star Office shares the same code-base as Open Office
The other alternative is Corel Wordperfect Office.