Today I finished cleansing myself completely of Microsoft Office, switching my e-mail to Thunderbird, my office applications to StarOffice and my schedule to Essential PIM, and boy was it a good decision. In addition to saving myself hundreds of megs of disk space and having my computer boot up in a fraction of the time (don't ask why that should be), my new free software is superior in every regard I can think of to the Microsoft alternative. It's smaller, faster, standard compliant and free.
A word of advice for those who have been too lazy or afraid to make the leap away from MS Office, do it! You won't regret it.