Libre office has the momentum and is installed by default in Ubuntu. I do not care enough about office software any more to install another that is almost the same.
I still use spreadsheets just about enough to install something a but different (Gnumeric is light and nicely designed - great if you do not need heavyweight features). As far as writing goes I increasingly want something radically different from heavyweight word processing. I use Lyx, but can see the appeal of some lightweight writing tools.
Things have changed a lot for me. 10 years ago my working hours were spend switching between MS Word, Excel and Outlook.
I love Open Office, my partner hates it. The difference is that, with a background in office automation, she uses spreadsheets as much as possible while, with a background in relational data modelling, the database is always my first choice.