Jabber/XMPP seems to make sense for a Skype replacement. It's a standard protocol and you can control your own jabber server as you can control your mail server. Google talk for example use xmpp.
I totally support you. I've been working with XMPP latelly and it is really great for colaborative development through the Multi-User-Chats (MUC).
Still, we use it in text-only mode, because since it has a standard for VoIP comunication, we haven't found any client that supports it correctly, and that's why we haven't totally replace Skype for it.
By any chance, would you know any VoIP supporting Client for this?
I see, I had not noticed that Jingle was the standard proposal.
Still, to really use something as an Skype alternative, voice and video are trivial! We will have to probably wait until Jingle becomes official, and meanwhile, still being with Skype...