@robots the good news are that all of these except for MSN are still alive and well, just not mainstream anymore.
I still use IRC, phpBB had a new release last month and there's BBSes available over telnet with new ones still popping up.
What I would like to see coming back to the mainstream is something like Jabber/XMPP so we won't be locked into using commercially owned IM clients that are mostly aimed at mobile devices and lock you into some corporate scheme.
Also an updated, opensource version of Hotline would be nice! 