I'm biased, so I'd say just use Apache ActiveMQ :)
Though I would recommend you evaluate ActiveMQ and JBossMessaging yourself; e.g. try looking at the features and compare the performance yourself.
FWIW ServiceMix uses ActiveMQ internally for its reliability, clustering, load balancing and failover mechanism. Though you can use any JMS provider such as JBossMessaging as a JMS component and bridge from any JMS (or other component to any other JMS (or other component).
Fuse: the Open Source SOA runtime