I use openoffice to
1. Edit simple web pages
2. Create documents, presentations, spreadsheets..
3. Create .pdfs from my documents
4. Open protected MS-Word documents (oops, maybe shouldn't have said that...)
5. Avoid paying MS royalties for my home machines.

I use MS-Word at work when someone sends me a doc in MS-Word format that they want back in that format.

I'll create docs in OO and save them in .doc format.