i'd start out with their debut, Only Way to Be Alone and then get their sophomore album, S/T and then this. a lot of people seem to dislike or not think as highly of their S/T but i love both (of their first two albums, i haven't heard the new album yet) and they're both very different in atmospphere and nature.
OWTBA is very acoustic, harmony driven and the S/T is much more "folkie" and features some neat moments of "Indian-type" music (with what seems like flutes and stuff). - and i apologize if that seems racist or cold to say, i don't know how else to explain it
both are very smile inducing and beautiful records, imo.
either way, you can't go wrong!