With all due respect, calicum scoring is old technology. If the patient can handle the contrast load you might as well do a coronary CTA on a 64 slice CT scanner at an imaging center that knows what they're doing.
Soft plaque is the killer and not detectable on a noncontrast cardiac ct. I've seen plenty of guys under 50 with zero calcium scores and lots of soft plaque including widow maker lesions in the proximal LAD.
With all due respect, I was asked what I thought about it in comment# 50. The abstract for the link I provided didn't strike me as a glowing endorsement for screening from a recent paper.