Well!
I particularly liked the blackouts; they're probably the best timey-wimey trick Moff's pulled off since Blink.
There's also something charming about leaving a million dangling threads and saying "Fuck it, let's go see pirates; we'll get back to this stuff in a few weeks."
Ending: well THAT was unexpected. The "Who is the little girl?" plot thickens. [spoiler]River and the Doctor's daughter? Amy and Rory's, somehow affected by the TARDIS and given a time head? It's probably safe to say the Doctor isn't the father of Amy's child. Could still be River herself, though hasn't it been clearly established that she's human?[/spoiler]
Another question that occurred to me after last week's episode: where's the future Doctor's TARDIS? Destroying his body so nobody can get their hands on it is fine and dandy, but leaving the TARDIS lying around doesn't seem like a good way of keeping Time Lord secrets safe.
Since he pulled up in a car, of course, it could be anywhere. Somebody else could already have it, he could have left it in 1960's England where it still looked innocuous, or he could have fixed the chameleon circuit and turned it into any object at all. Given the 200-year gap, it may not even be on Earth; he could have parked it somewhere else entirely and hitched a lift.
And of course it bears noting that the 200-year gap explains River's references back in Silence/Forest to a much older Doctor.
EDIT: Oh, and of course, how slow of me -- the very first time we ever SAW River, she was wearing a spacesuit. Not 1960's vintage, of course, but still, spacesuit. With her face covered and everything.
EDIT 2: Also, I was remiss in not mentioning the crazy guy's performance. It really was the best thing about the episode.
Also also: I doubt we'll see Nixon again, but I'm sure we're meant to believe there aren't actually 18 minutes missing from his tapes, just 18 minutes that nobody can remember immediately after listening to them.