Can I just point out the Face of Boe can't (logically) be Jack? FoB doesn't flirt with the *cat lady nurse nuns*. Jack totally would, it's his *thing*. And stays dead. Ergo, Jack cannot be the Face of Boe.
I showed my little brother The face of Boe and he couldn't stop laughing and I had to explain who he is and legends and stuff like that. And Jack is the face of Boe. I didn't see that coming when it did.