I'm officially a Digsby fan:
This little piece of FREE software is exactly what I was looking for. I wanted a single piece of software that I could use to manage all my social networking, IMs, etc.
Digsby fills that role and more.
Chatting with your Facebook friend is as easy as chatting with a GMail contact. All in one interface.
Additionally, Digsby provides a chat widget (right side of this website) that allows visitors to chat with you in real-time right from your own website! I've been wanting this for a long time and was contemplating writing something myself.
Now I can have my cake and eat it too!