This isn't voice acting so it doesn't count, but the sound of Andre's hammer striking his anvil is the most comforting sound to me. That little three-story tower is the safest feeling place in all of Dark Souls for me, moreso than Firelink Shrine. From the first time playing it when I was running around the Undead Parish, horrible at the game and begging for a bonfire, and every time I had to retreat there because I got fucked up in Sen's Fortress.
It's also what I thought of at the end of Endgame's credits lol.
For voice acting I agree with Laurentius. He always tries to repay me for helping him out and every time I tell him I'm not into pyromancy he says "Oh really? .... well, that's alright then". It's so earnest. I know the guy feels he wants to get me back and I wish I could let him know him being there is enough