i use the moz
gstreamer plugin for sound, and have gstreamer
configured to route via JACK. works great about 98% of the time.
Ummh "gstreamer" .... I'm not "g" and also not "k" and
I vote for create the WWNJNF (World Wide not Java not Flash).
mozilla-mplayer or mplayer-plugin, whatever the name is, works well
with jack. neither "g" nor "k".