Saupak has done about a good a job as I've ever seen of breaking down exactly when patch 2.3 might actually appear. There's a bumpy future ahead for the next two months-- it's full of holidays, vacations, and events, and so it'll be very interesting to see when Blizzard decides to insert Zul'Aman into Azeroth. Of course, the last patch dropped right when I was meant to be playing the just-released Halo 3, so there probably are no sacred cows-- Blizzard patches when they want to.
However, there are a few hits. We know the patch isn't going live today. The 13th and the 20th are out, because Blizz wants to give us notice, and Thanksgiving is right around the corner. That leaves the last week of November, and the first three weeks of December (very unlikely that Blizzard would drop a patch on Christmas or New Year's, because they've got to take a break sometime). Other than that, we're looking at the 8th, 15th, or 22nd of January.
Saupak's big bit of reasoning is that there were 168 days between 2.0 and 2.1, and 126 days between 2.1 and 2.2, so his guess is January 15th for the patch-- 105 days between 2.2 and 2.3. But remember that 2.2 was delayed so long because of the sound engine problems, and we don't have that with 2.3. And Zul'Aman is more or less done. So if I had to guess, I'd say we're looking at an early December patch-- either the 4th or the 11th (we've got to see an update sometime then anyway, for Feast of Winter's Veil). If we don't see it by then, then yes, my guess is that we're looking at January. Blizzard may try to squeeze it out before Thanksgiving, but I don't think that's likely. I do think they want to release it before Christmas, though-- and leave 2008 for the year of the Lich King.