When I first started listening to indie music, one of the first bands I discovered was Beach House. They were unlike anything I'd ever heard before, and anything I've heard since. Their music defines any label that you might try to put on them. They sometimes border on a post-rock, atmospheric sound, but that is a far from perfect definition. Their music requires exactly how much concentration you're willing to give it. If you put it on in the background while you write a paper, it'll calm you down and keep you focused. But if you want to be actively engaged, there's more than enough going on to keep you interested. Listen to "Silver Soul" after the break.
That was a great song. I really think this would make a great sample for a rap beat. Oh wait.