As a general rule, I like my tobacco bone dry. I find it smokes a lot cooler, stays lit easier, tastes better, and doesn't bite. However, you do have to find the right balance with some tobaccos. Some cased tobaccos to taste a little better with a little more moisture in them. I'm an extreme case though and I find I am willing to sacrifice a little bit of flavor for a better smoking tobacco. The reason? Those relights can fry the tongue and render the bowl tasteless anyway!
One caveat: Only dry out a few bowls at once. You want to smoke it dry, but store it moist!