I discovered, entirely by accident, that Command-Tab lets you cycle through the applications you’re running and pick the one whose windows you want to be on top.
Similarly, I accidentally hit Command-Shift-4 and discovered it gives you a cursor to take a screen shot. Further investigation revealed that Command-Shift-3 takes a shot of the whole screen. They both deposit PDF files named “Picture 1”, “Picture 2”, etc. on your Desktop. This one is actually useful.
If you enjoy the “genie” effect (sucking a window into the dock) or the “Expose” effect (showing all windows at once) on MacOS X, try 'em with the Shift key held down.
Open a half-dozen Straight Dope threads (or a half-dozen Word documents or whatever) and then try Command- ~ (command-tilde; actually shift key isn’t necessary so I guess it would be more accurate to say Command-` but that’s hard to make out in print).
Compare it to Command-Tab when you have a half-dozen apps open with a half-dozen windows apiece.
Go open a Finder window. Find a folder with a handful of subfolders, some of which have subfolders of their own (preferably without a bunch of loose files though*) and set the View to List View (Which, in case you hadn’t noticed, is Command-2, try it). Do a Select All (Command-A) and then do Command-DownArrow. When it’s done doing what it does, do Command-Option-W.
Go back and open the same Finder window you started out with. Set your window view to List View again. Do Command-A again to select all, but this time do Command-RightArrow. Do Command-LeftArrow to put it back the way it was. Now go Command-OPTION-RightArrow and notice how it expands on what Command-RightArrow does.
OK, and if you’re curious and don’t mind tying up your computer for a moment or two, open a big folder that DOES have a bunch of document and application files as well as folders; set it to List View, do Command-A, and then do Command-DownArrow, and then sit back and watch.
This only does something if you’re using some inferior browser that demands that you use separate windows for everything. I know that someone with access to the sublime pleasure which is Safari isn’t doing something like that.
Mine doesn’t demand separate windows for browsing, but I do. Just don’t like tabs. Can’t open more than about 16 concurrent threads in tabs and still have any notion of which is which without actually going to it. With separate windows, I can go to the Window menu and see which ones I have open.