For those who want a free office suite, Openoffice.org or Libreoffice.org are the most famous. Not to long ago, however, I came a across another contender in the field-IBM Lotus Symphony. I like it mainly because it puts all of my documents-spreadsheet/text editor/presentation-in tabs on one main screen. This way I can easily skip between files by using the tabs. The program is free, but you do have to register to get it. Try it out, since it does not cost anything.
Another interesting option is to buy Ashampoo´s office suite which you can often get for $5-10 on sale. If you download a free version of their older products, they will soon start sending you offers.