Summerteeth (to me, this album is Wilco, but thats because it was like, THE album in high school). "She's A Jar" is one hell of a song though, Christ in heaven man, talk about great songwriting!
I'm honestly not the hugest fan of A.M. as a whole, but "Passenger Side" makes it worth the asking price. Of course it helps that my friends and I were a bunch of drunks, and one friend in particular lost his license due to DUIs and drug charges several times.
I think the new album, Sky Blue Sky, is fantastic, but its much less experimental then its predecesors Yankee Hotel and A Ghost Is Born.