I'd scream. Not of exitement, because I'm scared my house gets the Uglyness-Virus! Then I would kick his imagination-balls and THEN I call the cops and say that he attacked me and I just defended me. Then he gets arrested. Oh wait...Babys can't get arrested!!! Too bad... (my face would look a little like this XD)
The warrior in me would kick in (well...my warrior never actually leaves :D) and I would karate chop him in the throat and kick him in the teeth. The I would just plain scream in his face until he left.
After he left I would treat myself to a hot cocoa, even though it's August.
This would be my reaction. "GET THE HELL OUT OF MY HOUSE u CREEPER! JUST BECAUSE YOUR DUMB SONGS ARE PLAYED ON THE RADIO EVERY SO OFTEN DOESNT MEAN u CAN COME IN MY HOUSE! LEAVE of I'LL FILE A RESTRAINING ORDER!" Yup.
zei hi with a kind way... and when i shake his hand, i flip him over and then scream "HOW DARE u COME TO MY HOUSE!!!!!!!!!!!! u ARE NOT WELCOME HERE!!!!!! u EVEN NOT CLOSE TO BE A SINGER!!!!! AND IF u DARE TO SING AGAIN, u WILL END UP DEAD!!!" after that, i kick him in his you-know-what. :)