I love to hear the whisper of my lover's voice in my ear, and his heavy breathing on my neck indicating his urgency, when we are intimate. I love it when he talks dirty or when he says soft, warm, mushy things... or when he tells me what he's about to do to me. Gets me all squishy just thinking about it.
I know some lovers are not so vocal... but personally I find it a confirmation when my lover can find the words to express what he feels, and also it's just plain simple: It's a huge turn-on. Then I will have an association of intimacy and sex whenever I hear his voice... and guys, isn't that just lucky for you? ;)