I have a Crumpler Wonder Weenie I picked up in London two years ago when I worked there. I used it mainly for the commute every day: change of clothes/shoes. It never leaked, but then again the London rain, while constant, was never very hard.

I have always thought very highly of Crumpler until today, which is why I am responding. I was riding back out to a suburb of Philly from downtown and got caught out in a horrendous downpour. When I got home I found my Crumpler had leaked all the way through - mostly around the back region where it presses against my back. Bummer. It doesn't have a seperate PVC liner inside like my Chrome bag. I will probably rely more heavily on my Chrome bag going forward, but I don't plan to eliminate the Crumpler bag from my arsenal entirely. I still think it is a good bag. Perhaps the larger sizes are designed to by more waterproof/courier friendly.