Spring-loaded exposé
Perhaps as many Mac users know, you can drag-and-drop files (and text) with the use of exposé (both the show desktop [F11] and show all windows functions [F9]). For those who don’t, here’s a video to illustrate followed by an explanation:
Press [F11] to show the desktop, then start to drag a file from the desktop, now press [F9] to show all the windows you have open (still keeping the mouse button held down). Then you choose the window where you would like to drop the icon and hover the mouse over it for a second or two (it will actually display a “no” sign, but if you wait then the window will come into focus) and you can then drop the icon there. This is useful for moving files between different finder windows, and as mentioned it can also be used with a block of selected text.
What most people may not know is that you don’t need to wait when you hover your mouse over a window in exposé mode; you just press the space-bar and the window comes into focus right away! This is why it’s known as spring-loaded. With a small amount of practise you can be moving files around very quickly, especially if you put the exposé functions as “hot-corners” (look in the prefpane for exposé, it’s very clear).