Since the undo command in vim will act as a re-do when the last command was undo, I have used uu as a means to go back to where I last edited. As far as I remember nvi will treat uu differently and make that two undos, but for vim it should work although some of the other answers are probably more proper ways to do this.

Since the undo command in Vi will act as a re-do when the last command was undo, I have used uu as a means to go back to where I last edited.

If you're running Vim with nocompatible set (as most people do), you want to use u followed by CTRL+R to undo & redo. Otherwise uu will work as in Vi.