I 100% agree with Dead Space winning for best sound. While I was playing that game, I was just constantly in awe at the games sound design.
So many subtle and cool effects, weapons sounded powerful, enemies were menacing, atmosphere sounds were moody and creepy, the whispering was eerie, the tram sounds, holographic inventory management sounds, the store sounds, upgrade bench, radio / video calls... it was all magnificent.
If only all games had sound design that well executed.
It's funny that this game won for best sound after I was musing about it to myself. Not surprising at all though.