There are several alternatives:
Per the above, NeoOffice is a good suite, and reasonably compatible with MS-Office, but like MS-Office, it is big and slow.
For MS-Word alternatives, consider Abiword, which is a very fast and capable MS-Word replacement. See
www.abisource.com. Abiword is small, fast and can read/write .doc files.
You may also wish to consider a web based approach to Office suites. Two notables:
1/ The new Google Apps package for doc/spreadsheet
2/ Thinkfree Office (
www.thinkfree.com) which is a free web based suite.