I expect oil prices will hover around $40/barrel for a bit here, especially if Kuwait closes its northern oilfields to protect them in case of US-Iraq action and OPEC is really producing as close to capacity as they say they are.
The US country analysis brief points out that as of November 2002,
The United States averaged total gross oil (crude and products) imports of an estimated 11.2 MMBD during the first nine months of 2002, representing around 57% of total U.S. oil demand. Around two-fifths of this oil came from OPEC nations, with Persian Gulf sources accounting for about one-fifth of total U.S. oil imports. Overall, the top suppliers of oil to the United States during the first nine months of 2002 were Canada (1.9 MMBD), Saudi Arabia (1.5 MMBD), Mexico (1.5 MMBD), and Venezuela (1.4 MMBD).