There's a big security hole if you're using Xmorph [Editor: a theme-switcher for OS X]. Look in ~/Library/Preferences/Xmorph Preferences. If you've authenticated once, you should be looking right at your admin password. The author insists that this is a "feature." Feature or not, no password should ever be stored in plain text. Another Real Basic app...
[Editor's note: See the comments - this 'hole' is completely optional and at the user's discretion. Seems like a reasonable balance of ease-of-use and security - you choose whether or not you'd like your admin password saved in cleartext.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20010713145626274