I preffer to use the best and more stable version of Microsoft Office. Version 2003!

Also, OpenOffice have many more(and better) features than Microsoft and other commercial offices suites.
One of the best features of OpenOffice is the one-click PDF creation. In Microsoft Office Word, you need to install 3rd party softwares to add a virtual printer that creates the PDFs for you.
Also, in OpenOffice you have a cross-platform program and format, that you in nearby any OS can edit and read your files. PDF is a good and very cross-platform format, but you can't edit it in any platform.
Another good alternative is Google Docs, but it have a lot of limitations. But at the other side, you can open and edit files that any OS that have internet connection and a good browser.
But the office pack choose is very personal. I have my favorite office, you have another and it's like cars and OSs.