Clipomatic is a very simple freeware program that keeps track of the last 10 items in the Clipboard and also allows you to have permanent entries that you can paste as well.

In the words of the author:

Using Clipomatic is simple. All you have to do is start it up, and it will start monitoring the clipboard and recording its changes. When you want to paste an old item, you just put the keyboard cursor where you would like to paste and press Ctrl-Alt-V instead of Ctrl-V. A menu pops up with your clips – you can select one with the mouse or with a single keystroke. The menu then disappears, and the item is pasted with no further work on your part.