Depends on how it's carried out, I think. Death's a pretty heavy subject, so generally, it either adds atmosphere or emphasizes something important about the plot or characters -- especially the plot. In short, you don't want to get too cliche and do it just because the villain is a villain. There's got to be a motive or a reason for the death that contributes to the story. (That is, death itself isn't an element to add to a story. It should be a vital component to it.)
So, if it's necessary to the story or to understand the way the villain's mind work, then I really don't think you'll have a problem having said villain go out and kill again.
At least, that's how I feel about character death.
