I discovered a workaround for the bug in Amarok that was preventing me from adopting it as my primary music player.  Full details are in the bug, executive summary follows:

• I disallow outgoing connections from all PCs on my home LAN as a security measure to guard against spyware and spam bots.
• Amarok uses two different proxy settings - one for streaming data and one for submitting last.fm track info.  The former is configured in Amarok and the latter in the KDE control panel (kcontrol).
• When no proxy is defined for track sumission, my firewall denies the outbound connection from Amarok, and it hangs (this is the real bug).
• Because i'm a GNOME user and KDE doesn't default to honouring the http_proxy environment variable, there was no exposure of my incorrect KDE proxy setting anywhere else.

Now after setting the proxy server by running kcontrol from the command line, i'm rockin' with Amarok!