Well the first song I learned by Muse on the piano was Exogenesis Symphony Pt. 3 (Redemption). The first few minutes of it is fairly easy as it is just fairly slow arpeggios as base notes and one treble note per chord. It gets a little bit more trickier during the "chorus" of the song, but it's good to start out getting to do two different things with your right and left hand on the piano.