AMQP is a complicated, single purpose protocol, and history suggests that simple general purpose protocols get bent to fit, and win out. Tim knows this trend. So here’s my current thinking, which hasn’t changed in a long while - long haul, over-Internet MQ will happen over XMPP or Atompub. That said, AMQP is probably better than the WS-* canon of RM specs; and you can probably bind it to XMPP or adopt its best ideas.
Personally, I see AMQP on the one side and AtomPub/XMPP on the other side of a fence — AMQP internally, addressing the same problem domain as current, proprietary queueing solutions, and AtomPub and XMPP over the Internet.