White House communications director Dan Bartlett explains why Dubya has not publically referred to particular casualties or incidents in Iraq, nor attended any soldier's funeral:

"He never wants to elevate or diminish one sacrifice made over another," said Dan Bartlett, the White House communications director. ...

"If a helicopter were hit an hour later, after he came out and spoke, should he come out again?" Mr. Bartlett said. The public "wants the commander in chief to have proper perspective and keep his eye on the big picture and the ball. At the same time, they want their president to understand the hardship and sacrifice that many Americans are enduring at a time of war. And we believe he's striking that balance."

Likewise, the military's new ban on photographs of, well, any particular flag-draped coffin returning from Iraq was instituted, no doubt, to make sure that the relatives of all the dead in Dubya's war feel that their sacrifice is getting equal respect...

For what it's worth, the Times article from which I took these quotes also says, "Mr. Bush does send a personal letter to the family of every soldier killed in action and has met privately with relatives at military bases", though no details are given. I'm sure Dubya personally would love to say more, but Mr. Bartlett just won't allow it...