"Waterproof" bags are overrated. Water will seep in there anyway. And the rubberized bags just hold moisture in, never letting it evaporate. My advice is to ignore claims of water resistance. Just get a normal bag and be sure to wrap electronics very securely and keep clothing and such in plastic bags (trash compactor bags work especially well).
I can say without reservtion and from a lot of wet weather riding that Ortlieb handlebar bags and panniers ARE waterproof. Holding moisture in" has never been an issue. My camera was in my bar bag on a trip this summer where we experienced 35 days of rain. My camera never got wet, was handy , and is still working great. My wife carried our netbook in one of her rear panniers and it was kept dry throughout the trip. I'm posting this with that netbook
Hiding out under the bridge this summer waiting for the rain to slowdown.
Oregon Coast after my wife was literally blown over twice, and it is literally raining sideways. We did take our bar bags off because they had all our valuables in them and we were going inside where it was warm!
the orange cover on my saddle is the useless rain cover from my old bar bag
