Clearly, the war was all about oil. Just look at the low oil prices.
Obviously low oil prices wouldn't have been the result even if the war was completely for oil. Breaking up OPEC would have been a much more significant goal than simply increasing supply. Anyway, it's pretty hard to deny that oil was a least a factor in motivation (you can't separate Iraq and oil), and we DID get it, so obviously there's some other agents at work.
Anyway, I always find it amusing that there seems to be a serious lack of competition between the oil companies. Out here in rural California, it should be MORE expensive than the bay area, due to transportation and quantity sold, however it's far cheaper here than gas stations right across from the oil refineries on the coast. If true competition existed, someone would charge less and force prices down.