A quick word of warning.
Oracle (the new "owners" of Open Office), look as though they want some money for a product that is quite popular and so the future looks a bit grim.
There is a new offshoot (fork is the term used) called Libris (I think, spelling may be wrong)
A battle is looming.
As for MS Office, get the home/student version, cheap and up to 3 installs IRC.