Moving something is just dragging it to the new loacation, unless its on another volume, then thats a copy.
To create a copy of a file in a different folder, you hold down the option key and then drag. The plus sign indicates that its not a move but a copy.
Well, in Windows I can cut/paste a file to a new folder without having two windows open, or copying when moving to a new volume. I'm pretty sure they have the command by now, and I haven't found it. God forbid Apple call it "cut" though.