Which open document format?

[Alan Dayley]

A coworker and I are looking to use an open documnet format but are not sure what to pick.  The company has used Lotus WordPro for years and is currently experiencing MS Word creep.  We want to start creating the documents in a format usable (viewable and editable) by the most number of word processing tools possible.  

So, the general requirements would be:

1-A format readable and writable by as many word processing applications as possible.

2-The document format intended by the author is predictably maintained (tables look right, columns correct, images in the right place, etc.) no matter what application is used to open, edit and save it.

I am fully aware of creating PS or PDF files for electronic distribution of such documents.  This helps a lot.  However, I am looking for a format that allows me to create the document in one application and allows some other person to load it in another application and edit it, without loosing my original format in the process.

For example, if I create the document in OpenOffice.org Writer and save it, a coworker should be able to open it in Word and add his chapter and another coworker open it with WordPro to add their part.  Then, I open it again with Writer and all the new stuff is there, appropriately formated.

Is this the "holy grail" of document formats and does not (yet) exist?  If so, what file format comes closest to this virvana?

Alan