We captured Saddam Hussein.
We have dismantled Iraq's ability to attack our oil sources in neighboring countries.
The rest of the Muslim world (and North Korea) has been shown that we will fight back if provoked.
Qadafi in Libya has seen the light and has turned over his WMDs as a result of Iraq
We have proven the existance of WMDs
We have ended the diasterous oil-for-food debacle and have re-established full trade with Iraq
What went wrong? Almost nothing.
You left out the most important one---the Iraq war attracted Al Queada operatives in droves into Iraq, where we are killing them off, thus helping to keep them away from US soil and targets.