I just upgraded from a cyclocross bike (Specialized TriCross) to a road bike (Specialized Tarmac).
If you're wavering now, I'd go with a cyclocross bike. It is versatile, comfortable (I took mine on some 60 mile rides), and you'll get some solid miles out of it.
Check with your shop to see if they rent bikes. I started a now-lengthy thread like this a few weeks ago. Everyone told me I needed to ride 30+ miles before deciding. I rented 2 different bikes, and the cost of both was credited to my purchase. I rode each ~90 miles, and was able to make a good decision based on what I thought.