Seminal albums from my youth: Nevermind, Ten, Green, The Blue Album, Chutes Too Narrow, The Boy with the Arab Strap, Thriller, Born in the USA, The Joshua Tree, Yankee Hotel Foxtrot, Sea Change -This is just off the cuff, top of my head. I considered youth anything younger than 25. -You'll see that this number goes up as my age does. Is This It, definitely changed the landscape. All of a sudden everyone sounded like them and there were immediately a bunch of little Casablanca's running around imitating Julian.
Thing is, those are the seminal albums of my youth; just put on a decade's delay. I discovered Ten in about 2002, Weezer in '05, etc. Which makes me worried that there aren't any seminal albums any more. But to answer your question, American Slang by The Gaslight Anthem. Absolutely pins and needles, absolutely up to expectations. But that was quite some time ago. Seminal albums from my youth would be stuff like Illinoise, Hot Fuss, The Hold Steady's stuff ... I'm having trouble with this one.