If you're set on getting a Specialized bike, then the Roubaix is the best choice. I prefer the ride of the Cervelo RS, although you do have to spend a bit more than your budget to get one.

And 180 lbs is not really "heavier". I suppose if you are 5' tall, that would make you overweight, but there are lots of guys out there over 6' tall in the 180-220lb range that ride (I'm one of them).