is a (more or less) native port of OpenOffice.org (1.1) for Mac OS X. While this has been around for a fair while, I've never seen it mentioned on MobileRead, and it's nearing it's first "stable" release (plans seem to be for an official release around June 20th-22nd). It's already good enough for everyday use, and has all the features of OO.o 1.1 built in.
The only minor flaws I find in it are the non-OS X style for most buttons, dialogs, controls, etc. (but that's very easy to ignore, with such a powerful program), and the speed. It's a little sluggish on a 1ghz Powerbook.