Well, it's hard to deny that the reconstruction of Iraq has generated a fair few dollars for American companies. And a war is always good for the economy too, that much is certain. Was it morally right? Dubious. Was it good for America? Certainly. Nothing new there, after all, the UK did plenty of invasions and wars when it suited them ;)
Wars that are funded using surpluses are always good for the economy when you're financing it with surpluses and can plunder the target country in the end. This war was funded with borrowed money...and the plunder isn't looking that great. It was a good idea from a strategic perspective, the execution of the idea was terrible.