If you do a lot of copy-pasting, you might find it annoying that your clipboard has no memory, and moving information from various windows and frames is a chore.
CopyPasteTool is a one trick application that solves this problem. When running, a little icon appears in your system tray but there is no interface whatsoever. Instead, CopyPasteTool simply remembers everything you have copied while it is running. Now, when you paste with Ctrl-V, repeatedly tapping V will cycle through your copy history. As it just adds to the near universally known Ctrl-V command, it's completely intuitive.
CopyPasteTool is great because it's unobtrusive and really lightweight. You can install and run it from a USB pen drive too. On the downside, it only works for simple text, and the lack of an interface means you can't manage your copy history at all - which starts blank every time you run CopyPasteTool.
It may be simple, but it does what it does beautifully, and you may wonder why pasting hasn't always worked this way.