Alternatives to Word/MS Office

[marina]

I am thinking of buying a new G5 and starting to use OS X seriously, 
and the only thing I'd like to understand before deciding is - what 
would be the best way to avoid using MS Office, and continue sharing 
documents with Windoz users? I understand I could keep using my old 
MS Office in "Classic", but, as a general rule, I'd prefer to avoid 
running two operating systems at a time - so in a way, this is not an 
option (or rather... using my current copy of MS Office for Mac could 
be the fallback option, if nothing else can be done!)

I write a lot, and my requirements include the following:

- opening and using Word templates
- building TOC's and indexes
- working with complex tables
- adding headers, footers, and up to 20 footnotes per page
- working with long documents (300+ pages), with different page
   layouts within the same document
- document statistics (word/character counts)
- applying user-defined styles

Features I never use in Word, and therefore can easily do without, 
include template libraries, labels, mail merge, dictionaries, 
grammar/spelling tools and multiple-language support.

I have started researching the possible alternatives (as mentioned 
here by Chas, i.e. Appleworks, OpenOffice, Mariner Write, and also 
Nisus Express), and so far, I haven't been able to understand whether 
any of these would give me the features I need, and equal or better 
results/ease of use as Word.

I'm not against "splitting tasks" between two or more apps if one was 
not enough for all, and would highly appreciate any input!

Thanks,

marina