You guys covered most of the reasons why I adore the GamePad, but there is one more.
The Speakers!
They're really good, the sound that comes from them are very well tuned and I don't notice any kind of distortion, I find that it also adds to the gaming experience by creating a virbrant & upbeat atmosphere. Having a mixture of audio from the GamePad and the TV is fantastic especially in NintendoLand.