Originally Posted by soccerjoe5 
I can't recommend the Kata DR-467 enough. It's very affordable compared to the R-103. Not as tough but tough enough.
<snip>I was on the rice terraces for hours in the rain and a little water seeped in. But I'm always prepared with some plastic bags, wrapped my mac as soon as it started pouring.
I have a Kata R-102 (no laptop slot) and have been around the world with it - tough as nails. It's zippers (and seams) are pretty water-resistant even without the supplied cover. It has rained on my pack numerous times and not even a drop got in. (By habit, I only use one zipper-pull, so they meet at the bottom... that might have something to do with it.) That said, I think the Kata GDC line is over-engineered to the extreme... nearly bulletproof, but that makes them heavier than the "thin bags" to start with.
I also have an Kata GDC H-12 "holster," and it holds my K20 w/ grip and 17-70 with just enough room at the bottom for 50 f/1.4. Perfect for walking around...