'A great office suite that costs nothing'
Learn more: Learn Open Office.org & Tutorials for Open Office.org
Some great extensions: Modern Impress Templates
Professional Templates & Writer's Tools & PDF Import
Active Image Lotus Symphony put together by IBM is also free, yes free for business use!
Office live Microsoft Office has gone online.
Microsoft Office is the best known world and used throughout business,both large and small and educational institutions.
The ongoing costs are there for all upgrades and given most people only do basic word processing or spread sheets there are a number of user friendly & free alternatives.
docx-converter For converting Microsoft's new .Docx format
Google docs is free and available to all who have a Google/Gmail account
Sync Open Office docs with Google Docs
Star Office Free and available to all.They have a paid/supported version also. Based on Open Office.
thinkfree is a free online office suite.
Free Open Source Office program 'Better Faster Freer'
The internet clipboard. Copy and Past between computers
Fight the Bull
Find and eliminate jargon in your documents.
WinMerge is useful for finding changes between project versions, and then merging changes between versions.
Open and edit your files from everywhere!
Open IT Online is the best way to open and edit your documents from everywhere!
Its free and a great extention for Firefox .