Mine was Starlight, or was it Uprising? No idea yet.
Mine was Uprising
I had played "Assassin" and "Knights of Cydonia" on Guitar Hero World Tour, but that didn't really get me interested in Muse. It was just my first exposure to them.
Then I saw them performing "Uprising" live at the Grammys. I thought, woah, these guys are fantastic live, and thus a new Muse fan was borne.