For you, the only victory is defeat.
Bringing Saddam down was prologue. Keeping Iraq from going the way of Afghanistan in the 90's and becoming a haven for terrorists is the real struggle. We just moved up the timetable so we could deal with it on our terms and not be caught by surprise after a palace coup, sudden death at the top or insurrection by Shiites that would depose Saddam when we weren't expecting it.
That won't happen for years, unless they are forced out early.
That said we don't need more then 30,000 troops for logistics and advising.