Why are we in iraq?

Ok i want everyones opinion on this topic..........ive heard so much info on why we are there...whats ur input?........most people say we are there for only one reason, "OIL". and that we wasted our time because Saddam was not the one who was behind 911. it was Osama, and we dont want to catch Osama because his family has alot of $$ invested in the USA and it would really really hurt the economy and the presidents pocket.....what do yall think? i need more opinions.