I have the FirstGear rain suit (the "rain man" pants and jacket) and the HD boot covers.
I was bone dry in a hurricane last year on a 8 hour ride. My socks were damp but that was from perspiration. The top 2 inches of my shirt was wet because there is no real way to seal around your neck for that long, in blowing rain, unless you are in a Kokatat Dry Suit
Remember, just like a tent, you have to recoat the suit with a water repellant, as it wears off over time. Especially the seams!