The Impossible Astronaut

This has such a great vibe to it. By this point, I feel the series has done a really good job at selling us on Rory and Amy. So now we get this fun little get together with the Doctor and everything has this cozy vibe to it. And sure enough, that nice feeling gets instantly turned upside down. We see the Doctor getting murdered, and sure, the pay-off of all that can be debated, but here it is one hell of a hook that leaves us absolutely invested in what comes next and curious about what Moffat is going to pull this season. Remember, we didn't know his patterns or tendencies yet, so I remember watching this originally and really having no idea what was going to happen this season.

And then I think the rest of the episode basically delivers on that promise of something big, because we go to the White House and meet Nixon, and then the Silence show up. It's cool as hell and I definitely think it is easy to overlook this and Day of the Moon, but the two episodes are strong as hell.