CMS for Monthly Magazine?

I am working on identifying CMS' that can and have been used 
successfully for producing online magazines.  We put out a small monthly 
magazine (8-12 articles per month) and are interested in upgrading the 
website from static HTML to some sort of CMS.  We'd prefer to stick with 
F/OSS products.  In reviewing a number of the CMS', we've identified 
three so far that look promising:

* Plone
* Silva
* Cofax

I have been playing around with Plone and Silva for the last month or so 
and I'm pretty sure I can create what I need with either one of these, 
but I want to make sure I've done due diligence by reviewing all of the 
potentially viable CMS solutions.  I just recently found Cofax so I will 
need to review what it can do as well.  We currently have a dedicated 
server running Debian and Apache and prefer not to move away from this.

CMS Requirements:

* Document versioning
* Metadata for documents and images
* Being able to set a publication date
* Setting an archive date
* A online subscription option would be very nice and the software 
manages the user base subscription/expiration date
  (subscribe to premium content like certain articles)
* Ability to use photos in articles (our magazine is pretty photo intensive)
* Some sort of advertising options or at least being able to add our ads 
to the page templates
* Ability to template the pages (the easier the better)
* Security is very high on our list
* Auto Table of Contents generation
* Ability to run Polls
* Ability to use Forms
* Ability to list related documents based on metadata
* Excellent search engine
* Web standards compliant
* Extensible

So far I've looked at Plone and Silva and have also reviewed what 
PHP-Nuke and PostNuke can do and that's as far as I've gotten before I 
found this list.

Any advice that the wisdom of this list could provide would be greatly 
appreciated.

Thanks in advance,

Shane Graber
Advanced Aquarist's Online Magazine