You know how OPEC is over 50% Arab, albeit spread out over a dozen countries? Imagine if those Arab countries were a single country, a unitary empire as in antiquity. That's why we're friends with these countries - to have an excuse to intervene if any one of them decides to become a modern Saladin. If we hadn't done Desert Storm, Saddam might have unified the Arab world. Think about what that would have done to oil prices. Apart from oil-related repercussions, here's a historical footnote - the last time Arabia was unified, Arab armies got within 200 miles of Paris.
There's also the fact that Desert Storm is the first war in which 2/3 of our expenses were covered by the Saudis and Kuwaitis, who handed to us $40b. As allies go, the Saudi and Kuwaiti royals have been pretty staunch, although they've had to make allowances for a populace that is pretty anti-American. It's unfortunate that this is the case, but short of the deportations of their entire populations to Mars, we won't get friendlier governments in place than the rulers already there.
But also remember too, they are good for fighting among themselves.