I use Apache OpenOffice.

Google Docs is pretty solid, even if Google is evil

Data not on your computer is not you data. NEVER use the cloud for primary data working or storage.

I bought Scrivener a bit back, and it is nice, but complicated and rather confusing (it's Mac-native). I also have used yWriter, which also has a nice set of tools. Both programs, though, really lend themselves to LARGE writing projects, where you have a lot to keep track of. Since most of my work is short stories, I almost always use Notepad++ which is no-nonsense, simple, and fast. Back up to Dropbox and I'm done.

Rochndil, bringing low-tech to the party...

Open Office and a lot of words flow out of my keyboard.

I too use Open Office.