I'm in the same dilemna. I will test ride the Cannondale Cyclocross tomorrow. I just rode the Cannondale R600, which is a great entry level road bike; it weighs about 19 lbs; the Cyclocross weighs 23. Both, according to LBS, have same frame, same wheels, and componenets. The only major difference, from what this newbie can tell, is in the gearing. Acceleration is great on the cyclocross, better on the road bike. Top speed is excellent on the roadster, not so much on the cross. Roadster has three rings; cross has two. Cross can take larger tires; roadster, 30s max. LBS says the roadster will give me a better workout than the cross. You can put smaller tires on the cross and make a smooth ride, but the gearing will remain the same. I will have to ride the cross in order to make my final decision. Good luck to you. I'll let you know.

Urbanmonk