Our current web sites utilize the Wordpress CMS. We use the Wordpress database (MySQL BE) to authenticate users in some of our other applications written in CakePHP (MVC framework). We would like to continue using Wordpress for this reason and others (plugins, easy content modifications, etc). So the site wouldn't need to be built from scratch. We would essentially just need a theme for Wordpress to be built or modified.
Our "main" program is written in VB6 and is a standalone application with an Access back end, as Steve said. This program generates a space separated TXT file in which I use to populate a MySQL database. Then using Perl to parse the TXT file with complex regexes into XML, then use PHP to import the XML into MySQL.