I would have liked to hear my heros voice once in a while...i mean the deathknight is ok when you hear him but i would have thought that the contrast of the heros voice at times would be cool.
W/ the player speaking or not speaking: that wouldn't matter to me, really.
I've enjoyed games where I take on the role of someone and they are voiced-acted like GTA: Vice City...
...and games where the player never speaks w/ audio dialogue like GTA III and Morrowind.