Netscape icons get displayed in black and white. Icons have black backgrounds. My panel vanished. Whatever I say, I get no panel. But xmms won't play.
X can run at different resolutions.
Often they will pick a variety. If not a lot happens, and you are confident that your monitor and card can handle it, you can re-run the setup tool of your choice for X and feed it different values, or if you know what you're doing you can attempt to edit the XF86Config which holds the relevant values yourself. If you are still stuck with 640x480 or 800x600 and one of the huge things is the panel, you have a couple of options. First, you can use the arrows at the end of it and tidy it away when you don't need it. Or you can use the autohide feature so that it hides mostly offscreen until you move the mouse over it.