Alone
Y'know, Spaceman, for a self-proclaimed genius, you can be a bit of a dumbo.
That big face thing told you that you weren't alone, and you didn't believe him. You thought you'd killed all the other Time Lords, I get that.
But don't you ever think that maybe that wasn't what he meant?
Look around you, Doctor. There's me, there'll always be me. And there's Martha, Rose, Jack, Jackie and Mickey, the ex-prime minister for goodness' sake. And there's Torchwood and Sarah-Jane, and they're all fighting for you.
That face thing was right.
You're not alone.
And you never were.