OpenOffice.org - Writer
What Word is to Microsoft Office, Writer is to OOo. The word processor is a very powerful one, enabling users to change the toolbars like MS Office and install additional languages for spell-checking. There are also many time-saving tips already embedded in Writer. One of them is “completion," which remembers the words you type and saves you from typing them again. You may find this annoying and can turn on/off this feature easily. You need not go through detailed menus.
One of the most notable features of OOo is its default PDF exporting capability. This was long a discussion point with Microsoft Office 2007 about whether to put this capability in or not, but it comes with OOo and is just one click away. Editing PDF files is not supported by OOo 2.x versions, but with 3.x versions, you can install a PDF Import extension and make some basic editing. You can not edit the elements shown in boxes. If you need to convert multiple OOo files to PDF files, then you need to use this macro. You can also set PDF permissions before making the convertion. JPEG compression, reducing image resolution, and making tagged PDFs are also supported.
Aside from PDF documents, you can also work with multiple file formats. The default file format is .odt for Writer. If you want to convert multiple files to OOo format, you can do that with batch processing. OOo is able to open and work with many file formats however can not save them all. Except from Microsoft Office 2007 format, you can save your work as HTML, XHTML, BibTeX, LaTeX 2.0 e and MediaWiki. You can just go through File → Save As and choose the format that suits your purpose.
OOo has all the tools that you need for word processing. The default formatting features for written text, tables, images, plus headings, page numbers, and revision control are all there. You can make some basic editing of your images (rotate, resize, etc) and also acquire images from your flatbed scanner. With the appropriate page formatting, it takes only a few seconds to make your index and table of contents.
If you are working with mail merge, you will find it in Writer. Envelope and label printing are also there for you to use. Users sending out regular mails to customers will find this very useful (and nobody is stopping you from using this feature for your friends and family).
Working on a file concurrently (editing a file with more than one user) is not currently well supported. There is no support for this at all in OOo 2.x, and in 3.0.x you can use this feature in Calc only.