But my problem isn't knowing how to change the theme. it's that the default Cassandra theme has different icons in it now. The Cassandra icons are now the same as Bianca's icons. In other words when I have the Bianca theme selected and change to one of the two Cassandra icon themes, the icons stay the same, there is no difference between the three icon themes.
I hope this explains it better. It isn't too urgant. I really liked the default icon theme but since the proper icons are no longer there, I went to http://www.gnome-look.org
and dressed up the UI a little bit (including the icons).