-- The site that you guys work on is suitable to be developed based on some existing content management frameworks/systems-- some open source CMS systems already integrate BBS/blog/groupware modules well and reduce the work to put together different systems. Check out www.opensourcecms.com for php-based systems, or here for open source ones.
-- PHP/mySQL base systems is known for scalability issues. Dependent on the future direction/traffic growth, this may also be an issue in the long run for Haiguinet. Also finding experienced professional PHP developer is not as easy as finding J2EE/.NET developers. Overall ASP.NET may be a better choice because of the novice-friendly IDE support although I personally prefer J2EE since I am such an anti-MS paranoid:)
-- Nukes of JBoss is a port of the PHP PostNuke system which has lots of useful modules ported from PHP, including the phpBB. This is a good Java based system. There is also a very good open source struts/J2EE based BBS system developed by chinese at www.laoer.com.
-- DotNetNuke is a M$ sponsored open source CMS system on ASP.NET platform, although the feature is currently quite limited compared to PHP /Java systems above. ASP.NET forum is a phpBB style forum written in asp.net.
-- You do need some pro artist/page designer for the look&feel. the current haiguinet.com front page is ugly