looks like Gates may have some policy difference with Rummy. But in the end, Bush sets policy.
It seems that Gates predicted many of the problems the US would encounter in Iraq back in the early 1990s when he was serving under Bush 41. Hopefully he has an effective way to deal with the current situation. Rumsfeld did a lot of good things, but Gates is the right person to deal with the current situation.
What I'm saying is, this is sending a signal that Bush's policy is changing. Why on earth would he appoint a new Secretary of Defense with a contradicting philosophy at this stage. The only power Bush has going forward is with a "yes" man at his side. Rumsfeld wasn't a "yes" man and wasn't interested in pulling out of Iraq. Therefore, it seems to me, that the choice of Bob Gates indicates that he is in tune with Gates' philosophy at this point, not the other way around.