I had a chance to participate in an audio/video call last night using the new Msn Messenger(7.0 released 2 days ago). Though I used be quite active in this area (using NetMeeting mind you) I haven't actually used this kind of technology for a long time. I don't know whether the new Messenger is that much better than the previous version in this regard but I was pleasantly surprised at both the quality of the connection (both ends were broadband) and the ease of connection (I am behind a UPnP enabled NAT).
If this keeps up I may have to stop using my standard statement with respect to internet based VOIP:
"The internet is a very hostile place for real time audio/video calling"