Thanks to Andy for pointing out Alec's latest writing on the state and future of presence on the desktop/phone/net.. I have no less than 15-20 ways to be reached, and managing all these identities is just a nightmare. Quite frankly I just stop using some really great applications, for the sole reason I can't manage them.
There has been some great debate floating around the blogosphere on this, I am sure it will continue after the holidays.
Alec's Post on Presence.