As I've noted before, the party conferences are among the few political events that can have a visible effect on the polls (the Budget, which led to a sustained fall in support for the Tories, is another). Labour won a bounce from Ed Miliband's bravura speech and it looks as if the Tories have won one from David Cameron's.
Two successive YouGov polls have put the party seven points behind Labour, compared to 10-14 points before the conference, while Cameron's lead as "the best prime minister" has risen from four points to 14. It remains to be seen, of course, whether this is a temporary or a permanent shift (one suspects the former).
The latest figures (Labour 42%, Conservatives 35%, Lib Dems 8%) would still see Miliband enter Downing Street with a majority of 90 seats, but the Tories are comforted by the fact that the party has overturned much larger Labour leads in the past. In addition, they note that support for governing parties tends to increase in the run-up to an election (as it did for Labour and Gordon Brown).
However, as things stand, it's hard to see the Conservatives remaining the single largest party, let alone winning a majority. It cannot be emphasised too strongly how difficult the loss of the boundary changes has made it for Cameron's party to win. Based on a Labour vote of 35%, the Tories would need a lead of around seven points to win a majority. In the absence of a Falklands-style bounce, it's hard to see Cameron succeeding against Miliband where he failed against Brown. After all, no sitting prime minister has increased their party's share of the vote since 1974.