I figure a couple of the main reasons behind this war are that

a) there are all these neato toys that the US has been working on that they're just itching to try out in a real combat situation, and

b) you actually have a villian with Saddam. He's a proud SOB, he's got that evil dictator mustache going and he's not a nice guy at all. And he's not white. Nor is he black. In the Balkans and Rawanda/Somalia, there really weren't villians, and if there were, they were either politicians that looked a little too much like your average senator or they were impoverished 3rd World citizens. Hard to get your average American riled up about either (though I'm sure they'd be willing to attack a senator :)

And there's the oil, of course.