Yeah, I ride in the rain, sometimes even when I have a choice. My commute to the office is 50 miles each way. My choices are taking the Beemer (48 mpg), taking the Ford E350 (12 mpg) or riding Caltrain (inconvenient schedule). Given the time savings using the bike - one hour each way versus 1.5 to 2 hours in the van or the train - and the price of gas, I take the bike unless it's icy out. Last week I rode one day when the temp was 39 and the fog was so thick visibility was down to 100 yards in places. I've also ridden into town and back in the rain a few times lately.
It really isn't so bad, and make for a great excuse to get out of the office before rush hour. I have a BMW cordura suit with Gore-Tex liners, and the heated handgrips are a godsend in cold, wet weather. We don't get any warm, wet weather in California.
I rode in the rain quite a bit when I lived in Texas, and didn't have anywhere near the high quality riding gear I have now. One Thanksgiving I rode from Dallas to Kerrville (300 miles) in solid rain. The forecast called for party cloudy with temps in the 50s. By the time I reached Llano the temp was in the high 30s and there were snowflakes mixed in the rain. I had ice on my jacket, pants, and helmet when I reached my grandmother's house. Not fun, and I nearly froze.
But I'm committed to riding in the rain now. If it gets too bad I'll get an electric vest and electric gloves for the Beemer. At $2/gallon for gas I can't afford to drive that big-ass van every day.