I've been slowly going through their discography and finding my favorites.
Their self-titled Debut Album (2001) is garage-rocky and raw. Best track off of it is, by far, Spread Your Love.
But Howl (2005), their third studio release, is one of the best albums I've ever heard. Ever. It achieves the perfect blend of gospel-blues-country-rock. I love every single track.
Even if you're new to the band, you've probably heard Ain't No Easy Way (off of Howl).
Other fantastic tracks on the album are Shuffle Your Feet (my favorite), Promise and Weight of the World.
But the real gem is on the EP of unreleased sessions from Howl. Mercy is one of my all-time favorite songs. I don't know how it didn't end up on the album, because it's a masterpiece.