I'll second the Contemporary for Wishes. My DW and I were there in February and were lucky enough to see Wishes from our room. We didn't get to hear the sound, but the fireworks were fabulous.
We did notice that several of the other guest were at the observation deck and it sounded, faintly, that they were pumping the music in for the crowd.
The California Grille, located at the top of the Contemporary, would also be a very nice place to watch the show if you want the resturaunt atmosphere. We have been there to watch previous shows (not Wishes) and they turn down the lights and play the music. If you decide this sounds good to you, be sure to get a PS so that your dinner will coincide with the show. If in doubt it's better to arrive earlier, finish dinner, and kill time with dessert and coffee than make a PS late and get stuck waiting for a table. Be sure to request a window seat to see the show when making your PS.