They're a really hard band to describe. They're like a sort of mid-point between The Smiths & early English folk music. They encompass all sorts of influences to make incredibly unique music. Also, I believe Colin Meloy to be the best lyricist since Morrissey - certainly the most erudite, anyway. The subjects that he writes about in his songs are incredibly fresh and original, and unlike anything else around today. Their greatest album "Picaresque", for example, features songs about a joint suicide pact, two mariner's being swallowed by a whale (on "The Mariner's Revenge Song" - their greatest ever recording) and falling over during a football game.
I don't really know what else to say... I cannot praise them enough, and I urge you (and anyone else reading who already hasn't) to purchase 'Picaresque'.