I have the Craft Storm tights. They're great in very cold weather (they're VERY thick & warm, and have room to layer long underwear underneath), good in heavy snow, mixed winter precip, and maybe a very light drizzle, but I don't think I'd necessarily want to wear them in a downpour. You'd be better of with a lighter, more breathable tight with goretex overpants.

I also probably wouldn't wear them biking for temperatures much warmer than 30 degrees. They're really quite warm.