I use Pidgin (by MSN, AIM or Gtalk protocol) to talk to online and offline friends, telephone/face-to-face for offline friends and family, irc#eoff to talk to Shorty, Visitor Messages and PMs to talk to EoFFers who aren't directly available through one of the aforementioned.
I have an LJ, a MySpace, a Twitter and possibly even a Facebook, but only so I can follow friends-only journals/updates/whatever.