I've had good luck with the 40D in rain. LCD has had condensation on inside. When canoeing have put cameras in ziploc bags, which if you leave air in will float.

Just be careful, putting wet stuff in plastic traps the moisture in the bag. So don't leave a wet camera in a ziploc bag overnight or something, at least I wouldn't want to, might not work in the morning. wet 70 degree air cooled to 40 will probably lead to condensation, too: more moisture.