If you work in long Word documents, you're probably already using Bookmarks. Even if you are, you may still want to quickly find the last place you were working.
This is an easy thing to do, both in Word 2007 and Word 2010. Press Shift F5 right after opening a document to jump back to the spot where you last typed. (For best results, open only one Word document at a time.)
In Word 2007, if the shortcut key doesn't work (which seems to happen from time to time, at least for me), just go to the Insert tab, click Bookmark, and check Hidden bookmarks. Select the _GoBack bookmark and click Go To: