The fact that the Speech bubble (the little silver and blue thing that pops up when you activate Speech Control) floats on top of everything drove me nuts. I don't use it for much, except Chess, but it still bugged me. I found you can minimize it to the Dock, just like a window, by double-clicking on any part of it except the bottom tab. You can still use it while it is minimzed! Not an amazing hint but it might help somebody.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020507015029728