The fact of the matter is that Office is a decent features rich piece of software ( although it's overly bloated with 346 MB of space for an office suite - Standard - and over 650 MB with many add-in's ). Just because it's made by some evil OS company doesn't mean all software are bad. I like Visio pretty much ( even before they are bought out by M$ ) and I've yet to see any Linux package come close to that one.
What I think is that Operating Systems software is very much different from Application software and middleware. OSes should always be open, stable and well written. That's why I don't mind paying for an OS as long as it's free and opensourced.
For applications, I don't really mind a close source ( except those emulation piece of crap - IBM Websphere HTML Editor > ) software as long as it runs natively. And the software as features rich as MS Office can be a good thing for Linux. I'm the business professional who use Office inside and out. There is a good reason why Lotus Smart Suite was beaten by M$ Office. Lotus's was just plain :.
Finally, opening Windows source will be a good thing for many software developers ( outside of M$ development team ) as well as many users. Porting M$ office will also help those crappy Office suite offering in Linux to a good battle ground for innovation and advancement. And THAT will makes Linux compete in corporate environment and variable solution.