Way back in 1992 i used Lotus 123 as my desktop productivity suite . It had a word processor, spreadsheet and all. Then came Microsoft office with almost the same set of tools as Lotus. I used MS Office from 1995 till 2003. Thats when i learnt about OpenOffice - A free and open productivity suite , while attending a talk given by Atul Chitnis on Linux . Got a copy from one of the local ILUG members , installed on my laptop ( Acer ) and was amazed at the features it had to offer - A word processor, spreadsheet, presentation, database,html editor - wow, it had all that i needed, and the cost - Zero! - Ok maybe not zero if you consider the cost of the cd that i had to copy it on :-).
Today I use Open Office 2.0 and it takes care of all my productivity tools needs and best of all i can export as well as import MS Office files.
So if you do a lot of word processing ( letter, documents) , spreadsheets , presentations then take my advice - get a copy of OpenOffice today and save yourself a hell of a lot of money and licensing headaches.