There are many advantages to guerilla-type or terror-type tactics but there is also one great disadvantage which is particularly important in this instance: Once they demonstrate that this is the manner in which they are fighting they give themselves away and lose their advantages. They can only apply these tactics on the unsuspecting. When the unsuspecting are alerted, by an attack like this, they can easily take steps to prevent it.
I believe that our forces (our command) already is quite aware of the concept of Baghdad being a booby-trap for something truly horrible. That is why there will a siege perimeter around Baghdad (like there is right now around Basra). And when we have a perimeter we can concentrate our incredible fire-power advantage on their remaining forces and degrade them until there is literally nothing left.
We will not just try to triumphally march into Baghdad -- we will invest the city fully, and pound their forces in it at our leisure. This won't end in a few days. We will take our time.
I hope you are right and that our decisions will continue to come from our military rather than from political and beaurocratic hacks. I want Colin Powell to stay as far away from this as possible.