Currently, when you delete an applet from a panel and re-add it, you've
lost all that applet's preferences and you're back to the defaults.  If you
delete the panel, you lose the preferences of all the applets on there, and
you're back to the defaults next time you add them.  This sucks-- if I have
to type in SUNW and point gweather at Dublin one more time, I'll scream  :)

Ideally, any time you add an applet, it should use the same preferences
that were in force last time you deleted that applet from your panel.  Or,
if you already have another instance of that applet running, it should use
the preferences from that instance.  (If you have multiple instances
running, things get kind of sticky, but just picking the preferences from
any one of them would still be better than what happens now).

At the very least (but way more ugly), there ought to be a way of
specifying defaults on a per-applet basis in each applet's Preferences dialog.