The version of OpenACS shouldn't matter. I would pick that version based on your site's requirements, what it needs to do, when you need to launch, what resources will be available to develop and maintain it, etc., but there are others here who can tell you more about that.
The most recent nsvhr patches were developed with AOLserver 3.3ad13, the ArsDigita release patched and packaged by Rob Mayoff. That version is available from the ArsDigita site: http://www.arsdigita.com/acs-repository/one-version?version_id=2081.
That's what I would recommend.
