If you use TextEdit as a scratchpad for typing in notes, and frequently close it without saving them, you wish to avoid Lion's longer wait to open a save dialog (which you don't always want) than the previous 'Do you want to save?' dialog.
While even an empty document (you typed something, then deleted it) will prompt for saving, a document with no undo history won't. I've found it's quicker on my system to use Command+Z to undo everything I've typed, then Command+W to close the window, than Command+W to close followed by a wait until I can dismiss the save dialog.
[crarko adds: That Save dialog does take a unusually long time to pop up. I'll make a guess this is because the system is doing its housekeeping for Autosave and Versions. Anyway, the method in the hint was definitely quicker when I tried it.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=2011090812411610