Normally you would have to pay around $70 to get a copy of StarOffice, but as of last week it comes bundled with Google Pack.
StarOffice 8 is a full-featured office suite that contains a word processor, a spreadsheet tool, applications for presentations, databases, math formulas and drawing. It has support for most Microsoft Office formats (except for the formats introduced in Office 2007), but it can also export documents as PDF out of the box. It’s worth noting that StarOffice has a huge installer (more than 140 MB), so you should download it only if you have a fast/stable Internet connection.
Even though OpenOffice supports more languages I believe Google chose StarOffice because it includes more features and more pre maid graphics and layouts. Documentation and support are also better which makes the move from Microsoft Office easier. Google also made a distribution agreement with Sun 2 years ago.
Looks like Microsoft are facing some strong competition in the future…