In a large corporate environement, you may have little choice--they locked themselves by cheerful productions of non-portable forms, templates, visual basic-driven web pages and other "tools".

In a smaller environment, you can use OpenOffice.org suit (OO) that runs on Linux, Windows, Mac, Solaris, with full file-level compatiblity. It can be downloaded and installed for free (no restrictions whatsoever) so nobody should really complain about the file format (some control freaks still will). Just to make sure, it can import and export MS Word and Excel documents of reasonable complexity very well. However, its native file format is fundamentally much better (and non-propriatory). Feature-by-feature, it can do almost anything MS Office can, plus some extras. Depending on whom you ask, the ease of use veries between "50% more difficult" to "20% easier" (measured on experienced MS Office users). Very complex documents are best transferes as pdf, and OO can make them on the fly.

So, probably you do not need MS Office any more. Download your OO for MS Windows and Linux at: http://www.openoffice.org/