I recently bought a DA18-55WR to team up with my K10D as a weatherproof set, and I love it. The lens isn't very expensive (compared to other lenses), and it's weatherproof, so you get 2 kinds of piece of mind. Nothing will happen to it, and if something happens, it wasn't very expensive to begin with.
I recently took it on a long trip through the Philippines and southern China, and I'm very glad I did. I got some great shots with it, that I otherwise could or would not have taken because of the rain or bad weather (or my anticipation of it). As a Philipino I'm sure you know it can rain quite badly sometimes
Though it can't really be pushed to its extremes, the lens is capable of very decent Image Quality. I often mistake one of my photos as taken by one of my limiteds, while actually it was the DA18-55WR