I ride a lot in the rain (note home town in my signature).

Your comfort in the rain, and on wet roads, will be *much* improved with full fenders. A full front fender will keep a lot of moisture off your feet -- not just when it's raining, but also when the road is just wet. Make sure you either have a fender that is very long (like a Honjo metal fender) or put a mud flap on the bottom of the fender. That extra 3 or 4 inches of coverage makes a big difference.

On the rear, a full fender will keep more gunk off your bike.

You'll still get stuff on your bike, but you'll be much drier, warmer and happier.