Depends


If the game has full-motion or cutscenes, I want them voiced. But then I want the whole thing voiced, not just those parts. That's one thing I hate about Kingdom Hearts.
It's one way or the other! Not both! Drop it!
Cutscenes can be dialogued with text rather than voice-acting, but if you need to control the flow of the text so you don't miss anything, then the cutscene will be considerably slower.
Personally, I prefer voice-acting. It adds another element of immersion to the game. If I'm staring at a bunch of people who are gesturing or making faces and no sounds are coming out, I react the same way I do if there's no music or sound FX. If I wanted to play a text-based game, I'd pick up a text-based game.
I have mixed feelings about the voice of the main character. On the one hand, I don't want my character wandering around as a mute that other characters somehow understand. On the other hand, that's not my voice! There's no win, because the level of immersion taken from the main character is the same whether he has a voice or not.