http://www.habcycles.com/techstuf.html#oneinch

"Also, it's been suggested that an 'over-stiff' steer tube concentrates stresses at the ends, rather than distributing along the entire length as well as a 1" steer tube might. And after all, the ends are where steer tubes will break, not in the middle."

I dont' know if I buy that. Personally, I like the looks of many quill stems, esp the Cinelli 1R and the Shimano DA (made by Nitto).