Saw the Mission: Impossible episode called "The Mind of Stefan Miklos". Very subtle and complex, all about making an enemy agent think they're trying to fool him, so he sees through the 'deception' and believes he has won, but really the whole thing was an even more massive smoke screen to get him to believe disinformation. I was very impressed with it.
Randomly, my top five television theme songs:
1. Mission: Impossible
2. Angel
3. Firefly
4. The X-Files
5. Doctor Who