Major Word Processor: StarOffice/OpenOffice, because of its universal file format in ODF, it's roadmap, and the fact that it is Open source.
Sorry, but when I think of productivity software (word processing app is from this category) things I care first are features and productive UI as a way to get these features used. OOo is a good product, but it's definitely not better than MS Office from this point of view.
Source code availability is not a virtue for products like that: I'm not going to spend any time with compiling or modifying Writer for my needs.
ODF is an open format -- so what? I created document, printed it or converted to HTML/PDF -- I don't care about file format. But if you care, MS has opened formats.
In the end, despite its "open" moniker, the Microsoft MS-OOXML format remains strictly proprietary, as Microsoft refuses to disclose the difference between its published file specification and its actual one to other vendors and developers.
This is biased conclusion again. "Proprietary" doesn't mean "they have some other format for themselves". C'mon -- they're pushing their format to standards bodies! They need it to be open standard, because this is the key to govt institutions which are under open source influence now. Don't be open source zealot here!
Below is what a 6039-page spec looks like, and ask yourself if anyone other than Microsoft will ever be able to fully and correctly implement the specification.
Again, opiniated conclusion! First you complain they're not opening file formats, now you complain they have a huge doc for file formats.