Alltray saved my life.
OK, not really, but Alltray is the answer to one of the problems I've had with GNOME's panels. When I use GNOME, I have one panel up at the top of my screen, with a WindowList applet running in the center. This gives me lots of space for my work, but it also can cause trouble as it fills up with aplications. With Alltray, I can turn some of these windows (like the GAIM IRC window, which has been a constant eyesore to me since the buddy list neatly tucks away inro the notification area) into icons in the notification bar. In this example, I've turned the IRC window into an icon. Handy. Of course I can get carried away and turn everything into an icon, but it's mine to choose.
Now I can stop looking so lustfully at the MacOSX dock.