I've just found this extract from a 'National Safety Council' report from 2009.
"Anti-lock brake systems can stop more quickly than conventional brakes on wet paved surfaces and on icy or packed snow-covered roads. Stopping distances can be longer on loose gravel or freshly fallen snow, although drivers won't experience the lock-up of the wheels usually associated with conventional hard braking. Therefore, drivers will still have the ability to steer around objects in front of them—such as another car."
Sounds like some of you are right in that it does take longer to stop on snow but you won't be able to steer.