Chipper,
You may already be aware, but RedHat ECM/CCM is basically the ACS Core redesigned and rewritten in Java by the ArsDigita folks. Before they got bought out by RH, ArsDigita made the decision to go forward with Java as the platform for new versions. RH is continuing that work. It appears as they are working on PostgreSQL support for their next release.
Another OSS option you can check out is Zope (zope.org) written in Python. There are numerous commercial products which deserve research if you have a budget for such things.
Google for "content management" and you'll see that this is definitely a crowded space, everyone from Microsoft to unfinished sourceforge projects are vying for your attention.
Of course in this forum it's no secret which we think is best :)
Enjoy,
Ivan
