I think some of the best bikes for road biking and commuting are cyclocross bikes. They have the same aggressive geometry as most road racing bikes (although sometime slightly more relaxed), but a much sturdier frame and often come equipped with braze-on mounts for racks and fenders.
On the low end of the scale (although certainly not cheap or really that inexpensive), I'd consider a Bianchi Volpe. Some other slightly more expensive options would include a Surly Cross-Check, a Kona Jake, and a Lemond Poprad or Poprad Disc. All of these bikes work make for great dual purpose road racing and commuters.
I'd hesitate to ride a pure road bike like the Trek 1000 commuting. Some people do it and absolutely love it. I don't, however. I prefer my commuter to be much more sturdy and a little more upright. When I bought my road racing bike a couple of years back, I anticipated commuting on it quite often but not only was it not that comfortable for it, it just wasn't well suited for the task. The tires were too thin, it didn't have fender mounts, I hated wearing my Speedplay cleats for a commute, and it felt too fragile or slinky for weaving through the potholes. YMMV of course.