There's a bunch of directions to go for a cold weather riding suit that is windproof/waterproof/water resistant. It's really about how much money you want to spend. One of the best options from Harley is their FXRG line of leathers. Pants have a breatheable waterproof liner, good leather outer, flexible armor. Jacket has a primaloft type liner that can be worn independently, or under the leather jacket. If the leather is treated with a good dressing, it will be waterproof in all but a toad strangler.
Another viable option is a really good set of snow skiing bibs and jacket. Most of the better versions are constructed of a Gore Tex shell, with plenty of insulation. Spyder is an excellent brand, but expect to get off your hip to pay for it. There are other good brands as well...check out a local ski shop.
Good leathers, if treated with good leather oil/paste will keep you amazingly warm with some 100 wt fleece long johns, or "expedition" weight long johns, and will keep you dry in most rains you'll run through. Throw on a windblocker fleece jacket under the leather jacket and you'll be good in all but extreme temps. If it's 35 and raining, I stay home...

The stuff Chief mentions is also great gear, but you'd look like a beemer rider
