Been thinking about this today for some time. Yes, I'm that bored... If I had to pick a winner, it'd be the weeping angels. The Silence have been around since the "beginning", but not necessarily the same "beginning" as the Angels. Reference Silence in the "Impossible Astronaut", they have been around from the beginning to shape humanity. Reference the Sally Sparrow episode, the Silence have been around since the beginning of the Universe.
However, the Silence - meaning that species and not the religious movement (citation: The Girl Who Waited) - are more than likely mortal beings. The Angels, being quantum locked and ageless, would ultimately endure. One might argue that all of the angels were sucked into the rift (Age of Angels), but that would only include those on that particular planet plus the one that was 'captured' in the vessel that crashed. However, there are still 4 known Angels locked in basement, and based upon that rift episode, technically anyone who has ever seen an Angel can create one in their presence just from memory. In "The God Complex", there is are 2 Angels in the room, created via hologram-type setting, but that should still have been enough to give birth to them in that reality. It might be deduced that since the Angels are never really found solitary, they hunt in packs, which would undoubtedly give them an edge over the Silence.
Side thought... If the Silence were to be wiped out (Impossible Astronaut), but reappeared in the alternate universe when all time happened at once (5:02pm - The Wedding of River Song), would that indicate that they are truly gone but only reappeared due to that alternate reality, or do you think that they will appear once again in a future episode?
Either way, I'd totally do Amy Pond.