im surprised that im the only one who seems to feel this way..
im just a cyclist who has put in 10,000 miles riding in WA, OR, CA, PA, and NYC in the past 3 years..
and the knobby in the back has saved my ass out of sh*t more than a handful of times, but a 1.5" specialized nimbus in the front has given me more than enough traction. even in the woods. (how much weight do you put on the front wheel anyway?)

Now, I notice the idea of more sand coming into play in this thread.. it really depends on what your dealing with. Those balloon beach tires are a good extensive example of this.. Its surface area that matters, sand is too loose to grip, so you gotta just roll over it fast. Because running the knobbys also means a slower, more buzzy ride when you ARE on the road (which is probably 95% of the time on your CX bike anyway). Sand will also eat/wreck your drive train if you use oil-based chain lube.

but unless your touring the sand dunes of Oregon, or somewhere comparable, you need not worry about washing out in minor sand patches on the road.

-=stevey