last couple of years it's been fairly predictable (fleet foxes & animal collective) but they've given it to some much less obvous stuff before. i reckon it'll be one of these four, in order of most to least likely

kanye west - my beautiful dark twisted fantasy
deerhunter - halcyon digest
janelle monae - the archandroid
joanna newsom - have one on me

anyone think anything else is in with a shout