Moderated comments?

On my blog comments every now and then an interesting discussion breaks out -- look at the first eight comments for this post -- but then, like toxic mold, one of my right-wing crazies posts something stupid and the blackness descends.
And boy, am I ever getting sick of them. I must admit, I barely read anything they say, its so garbled and meaningless and rude and bigotted.
I can't understand why they bother pestering me -- why don't they start their own blog, or go read Red State or Malkin or Dead Animals or the Blogging Tories or something? I don't read those blogs precisely because I am not interested in anything these people have to say -- so why do they keep putting comments on just about every post I put up, trying to insult me and the commenters whose opinions I do value? The only conclusion I can reach is that they're a bunch of 15-year-old boys who think its "fun" to annoy the grown-ups -- that seems to be about the mental age, anyway, and that's about the level of their reasoning
Anyway, I just can't keep up with banning them -- I try, but I think they're using library machines or something, because they keep getting back, often using new names.
So should I move to "moderated" comments?
I would likely only be able to check comments two or three times a day, once in the morning and maybe twice in the evening, so it moderating the comments would really slow down the conversation, but should I try it? Would people prefer this?