Dissatisfied with Sun/Oracle, some core constituents of the OpenOffice.org have formed Document Foundation and released a beta of LibreOffice (not necessarily its final name). They plan to integrate the improvements from Go-oo, but right now, there's no compelling reason to use LibreOffice compared with Go-oo. Stay tuned. Or not!

OpenOffice.org: http://www.openoffice.org/
Go-oo: http://go-oo.org/
LibreOffice: http://www.documentfoundation.org/download/