Go-oo is a variant of the cross-platform OpenOffice.org office suite. It has some more support for Office Open XML file formats than the official OpenOffice.org, plus a lot of other enhancements.
Go-OO has an enhanced interface and is much easier to use, with larger icons and sleeker interface.
It handle DOCX, XLSX, and PPTX formats, and natively supports SVG files.
Graphics rendering is greatly improved, too, including VBA support, Mono integration, better display of Chinese characters, support for WordPerfect graphics, and EMF rendering.
OpenOffice must be uninstalled before Go-OO is loaded.
Go-OO is free and open source.