When there is a chance of rain, I ride a 1986 Univega Arrow Pace (lugged steel mid lvl road bike) with a brooks b-17, sks fenders and large brooks saddle bag. It weighs in at around 40 pounds but it's a great bike with it's downtube shifters and biopace crank. Great for tooling around and whipping up on poseur roadies.
On nice days I take a 2007 Cannondale System Six with it's torture device derived seat. I dress like a super hero and don't go horribly faster than if I was on my old steel ride on the way to work. The way home is my time trial training which is working well I guess. I finally got a bike computer and I found out that I'm maintaining 26 mph on the flats and that I can sprint up to 35 mph on the flats!