Shapeshifter is an interesting tool which remembers everything you copy to the clipboard, and then allows you to choose exactly what you want to paste later.
If you've pasted an important piece of text to the clipboard, say, it won't disappear just because you copy some more text there later. Shapeshifter stores it, along with all the other images, files and anything else you've copied to the clipboard recently, so you can recall whatever you need without retyping.
This is all very easy to use, too. When you need to paste something, press and hold Ctrl+V and Shapeshifter's list of clipboard items appears. Use the up or down arrows to select whatever you need, release the keys and it'll be pasted into the application for you.
Just in case this isn't quite straightforward enough, Shapeshifter also displays pop-up messages when you first launch it, explaining exactly what you need to do, and when.
And there's even some thought given to your privacy. If you've copied something sensitive to the clipboard on a shared PC and want to be sure it's gone forever, say, just select it in the list and press Del. (Although if you regularly work with confidential information then we'd still recommend you close and restart Shapeshifter after a session, just to guarantee your safety.)