OpenOffice

Word Processor Writer – a word processor you can use for anything from writing a quick letter to producing an entire book.
Spreadsheet Calc – a powerful spreadsheet with all the tools you need to calculate, analyse, and present your data in numerical reports or sizzling graphics.
Presentation Impress – the fastest, most powerful way to create effective multimedia presentations.
Vector drawing tool Draw – lets you produce everything from simple diagrams to dynamic 3D illustrations.
Database Base – lets you manipulate databases seamlessly. Create and modify tables, forms, queries, and reports, all from within OpenOffice.org
Mathematical function creator Math – lets you create mathematical equations with a graphic user interface or by directly typing your formulas into the equation editor.

Native Mac OS X Version is called NeoOffice
Aqua integration Unlike OpenOffice.org, NeoOffice has native Aqua menus, file open and save dialogs, print dialogs, buttons, scrollbars, and many other native Aqua user interface elements.
No X11 software required NeoOffice uses the Java technology that is built into Mac OS X. By using Java, there is no need to download and install the X11 software that OpenOffice.org requires.
Integrated with Finder and Mail The Mac OS X Finder will automatically launch NeoOffice and open OpenOffice.org and Microsoft Office documents that you double-click on. Also the Mac OS X Mail application will open OpenOffice.org and Microsoft Office attachments in NeoOffice.
Uses Mac OS X fonts Unlike OpenOffice.org, NeoOffice uses the same fonts that all of your other Mac OS X applications use. This means that NeoOffice will handle reading and writing of Western European characters (e.g. characters with accents, umlauts, circumflexes, cedillas, etc.) and some fonts will even handle Japanese, Chinese, and Korean ideographs. Also, NeoOffice is able to use any fonts that you install using the /Applications/Font Book application.
Handles international keyboards Unlike OpenOffice.org, NeoOffice will use any keyboard layout that you use. Also, if you switch your keyboard layout while NeoOffice is running, NeoOffice will automatically switch as well.
Native OS X printing support NeoOffice supports printing using Mac OS X’s native printing functionality. Like other Mac OS X applications, you can use NeoOffice to print, preview, or save a document to a PDF file.
Native copy and paste support NeoOffice supports copying and pasting using Mac OS X’s native clipboard so you can copy and paste text and images between NeoOffice and other Mac OS X applications.
Native drag-and-drop support NeoOffice supports native drag-and-drop so you can drag and drop text and images between NeoOffice and other Mac OS X applications.