just to chime in, a local chicago favorite is 'skapone'. and i know they arent from the US, but if you dont listen to the skatalites then you are no ska fan, they invented ska, rocksteady and reggae in the 50s-60s in jamaica. their bass player was the 1st openly rastafarian musician in jamaica, which if you think about how many dreadlocked reggae band there are, is a huge deal. i've had the priveledge of seeing them perform about 5 times and actually got to go backstage and hang out with them the last time i saw them, which was right before 2 of the main guys passed away. talking to the drummer and bass player who were there playing bongos when haille sellassie came to jamaica, waiting for the rain to end so he would come out of the plane, they had the best stories, one of the best moments of my life (next to my son being born, my marriage and my 1st mame cabinet) truly truly ground breaking musicians, and you cant help but shake your booty when they play, its music that makes you dance!
and i guess while we are at it, a lot of early wailers is full on ska, there are a couple of really good compilations of jamaican ska out there if you look around...
respect