I've arrived at my usual "problem" with these sorts of polls - namely, the fact I think of "Year of Hell" as one episode and find (very) mildly irritating to have to vote for only one part. So for the purposes of this exercise I'll vote for part 1, but it's really a vote for the whole thing. It's just that bit better than "Living Witness".
"Message in a Bottle" is, IMO, overrated. But to each their own.