My commute is 14 miles each way. My bike is a Jamis Coda Comp. It's a flat-bar road bike, steel, and is very comfortable. I added bar ends on it, which adds options for hand positions.

I have a rear rack and I use panniers. I have used a backpack and messenger bag, but I find them very uncomfortable, especially for a ride 14 miles.

I have a rear blinkie light (Cateye T-1000, very bright) and a good headlight (Nite Rider Trail Rat). I wear obnoxiously-bright shirts from alertshirts.com. I have fenders installed on my bike, but I ride in the rain. That's a personal choice, and from my experience, not many folks ride in the rain. For snow and ice, I have studded tires (different bike that is my icebike)

I would consider the Coda because of it's smooth ride (steel is much smoother-riding than aluminum). The bike has been no trouble to me in the four years that I have been commuting on it.

I would also consider a cyclocross bike with a rack and lights and such. Cyclocross bikes have dropped bars, but beefier wheels and tires. I would not ride my light racing bike because there are too many potholes and bumps and I know I would get too many flats on my 700x23 wheels. The Coda has 700x28 wheels. Besides, it's the rider who makes the bike fast...not the bike.

For me, biking to work is fastest. Faster than Metro (subway) by about 20 minutes. Faster than the car by about 10 minutes, depending on traffic. Traffic is a problem in the car, but never on the bike. Parking is a problem with the car, but never with the bike. Gas prices...I was commuting on my bike long before the gas prices went up, and I'm oh-so-glad.

The last thing that makes a huge difference is having a shower and a secure indoor place to put my bike. My employer is just great for providing these amenities.