Saudi Arabia is a theocratic monarchy. They use their money to spread religious fundamentalism throughout the Muslim world in direct opposition to American interests. Other than oil, they have nothing to offer. I'll grant you the existence of finely cultivated personal relationships, but those are simply means to an end, not valuable by themselves.
It is a more complex situation then it's made out to be. For all of its repressive attitudes toward religious freedom, press freedoms, and of course women's rights it also a highly developed state with extremely low levels of violence, a well funded welfare and support system, a high degree of economic and infrastructural development, and quite frankly an indigenous Monarchy that enjoys broad popular support. The al-Saud has had three iterations and their history dates back to the 18th Century, Imperialism nor Colonialism played any role in their coming to power.
Saudi Arabia is a state that is as much governed by the existing attitudes of a strong conservative section of its people, as it is about the influence and rule of the Monarchy. There are definite limits to the ability of the al-Saud to pursue reform, that being said I think a very strong case can be made for a track record of progressive reform led from above and abetted by evolving social and political conditions.
The agitators for democracy in Saudi Arabia at present come from a disingenuous Islamist network that has no real desire to see an Islamic democracy, only a chance to unseat the al-Saud, while at the other end of the spectrum you have a mishmash of minority liberals and Shia opponents. I think the situation is beginning to change as economic pressures mount, and the impact of globalized technology and culture expands its impact, but at present the greatest force for liberalization has come from the top down.
However, yes it is true that the Saudi's exported Islamism. This began in the 1950's and 1960's as a means to combat the rise of Arab Socialist/Arab Republicanism which was being used as a weapon by likes of Nasser to subvert and destroy the Saudi state. The cold war between Saudi Arabia and Egypt has only been matched in recent times by the one between Iran and the Kingdom. To fortify their rule in the face of assassination attempts, proxy wars, and attempted coups the Saudi's retrenched their religious credentials and created a network of allied Islamist parties abroad. However, this is not the same as funding al-Qaeda. While their religious activities abroad of been brought under a severe international and domestic focus given the nature of our post 9/11 world.
Historically Saudi Arabia has more often than not has been at the forefront of supporting US efforts in the region and abroad. They have backed and supported us in Afghanistan (twice), the Israeli-Palestinian conflict, Yemen (complicated but arguably yes), Lebanon numerous times, Syria (with independent but congruent interests), Egypt (during the Cold War), Nicaragua, Iran, the Soviet Union, oil prices and crude ouput (quite often with OPEC), etc.