The world's most popular office suite (I'm talking about document writers, spreadsheets, slides, etc.) is MS Office. Even Microsoft haters will often admit that Office is at least a decent chunk of software. Linux has some office suites that I would call almost
as good and in some areas (such as OpenDocument
support), better. A reasonable comparison of the three suites listed below can be found here
First, I'll say that by using Crossover Office you can run MS Office on Linux. Crossover is neither free of charge nor opensource. Unless you really need MS Office, I strongly suggest you at least give the below options a fair try.
The most popular office suite for Linux and other Unix-like operating systems is OpenOffice.org. This package contains a document writer, spreadsheet creator, simple database tool, a vector drawing utility, presentation/slide creation, and mathematical equation editor. Each of these tools can import and save in formats used by their MS Office counterparts. OpenOffice.org (OOo) can perform nearly all the same tasks as MS Office and a few more. Some people assert that there are some advanced features offered by MS Office that OOo can't handle; I'm sure this is true, but for the average user, OOo will work nicely. My primary problem with OOo is that it is super-slow. It seems to take forever to fire up Write; this seems to have improved since the latest version release, but it's hardly been solved. OOo is maintained by Sun Microsystems who also releases a commercial version of OOo called StarOffice; for a little green you can get a few extra features and commercial support, but it's essentially the same thing as OOo.
KDE provides an office suite called KOffice. KOffice provides all the software you'd expect plus a few others like a diagram drawer and project management tools. While KWord can import MS Office file formats, it can not save in that format (the same is true for the other applications); so if you have to be able to provide your work to other people who do not use a word processor that supports OpenDocument, you might want to look at another option. KOffice seems faster and more agile than OOo, but like OOo it has all of the most commonly used features of MS Office.
GNOME Office is a collection of programs commonly used in an office environment. It includes AbiWord word processor, Gnumeric spreadsheet creator, The GIMP image editor, and the simple database GNOME-DB. Of the suites mentioned in this article, I have the least experience with GNOME's offerings, so you might find more information and personal experiences elsewhere. But if you're a GNOME fan or have been unable to embrace the suites mentioned above, you should check this one out for sure.