I tried Dropline GNOME once but it didn't really agree with my system, I kept getting graphical glitches, particularly in the menus.
I think I have the problem with gnome-theme-manager worked out: It seems to be caused by my use of Sawfish as a WM instead of the default Metacity. Switching back to Metacity and restarting GNOME solved that problem. Since switching back to Metacity isn't an option (it's too bland and ugly) I think I'll just have to put up with this one.
Now if only I can get the other two problems, particularly the nautilus desktop background craziness, worked out...
is a screenshot. In the top right you can see the red X where the mixer icon is supposed to be and the grey Nautilus background.
edit2: Solved the Nautilus craziness. It was a simple matter of compile version 2.1.91 (I had 2.1.6 installed previously). That leaves only the volume control issue. Any ideas?