re: brake pads vs disk brakes. I have never personally used disk brakes, but I use cool stop salmon pads on alloy rims all rainy Seattle winter long, and find them to be adequate-- and I have to go down some serious hills too. Drum brakes would also be another weather proof option that I have not tried.

Full coverage fenders, rear rack, and pannier is super important for commuting comfort! Don't forget a secure sleeve and pannier, if you will be carrying your laptop inside as I do.